2. "You cannot teach a man anything. You can
only help him discover it within himself."
Galileo Galilei
"When you know something, say what you
know. When you don't know something, say
that you don't know. That is knowledge." -
Confucius
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3. OUR SERVICES
Business Analytics
Data Processing
Data Minning
Data Analysis
Data Collection
Market Research
Feasibility Studies
Organisational
Assessments
Strategic Management
Business Planning
Training (Softwares,
Test Preparations,
Management,
Leadership, Etc)
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4. PURPOSE OF TRAINING
•Equip our clients with statistical
SPSS
•Equip our clients with the skills
to manage data.
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5. MEANING OF STATISTICAL DATA
ANALYSIS
• Collection of methods used to process raw data
and report the overall trends.
• Process of systematically applying statistical
and/or logical techniques to describe and
illustrate, condense and recap, and evaluate
data.
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6. REASON FOR STATISTICALANALYSIS
Transform raw data into information
The general purpose of statistical analysis is to provide
meaning to what otherwise would be a collection of
numbers and/or values.
Provide a way of drawing inductive inferences from data and
distinguishing the signal (the phenomenon of interest) from the
noise (statistical fluctuations) present in the data
Statistical analysis procedures are categorized according to
the type of statistics generated; i.e descriptive, associative, and
inferential.
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7. TYPES OF DATAANALYSIS
Descriptive statistics portray
individuals or events in terms of
some predefined characteristics,
like measure of central tendency
and dispersion –Mean, Median,
Range, Standard Deviation, etc.
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8. Associative or relative statistics seek to
identify meaningful interrelationships
between or among data. Such statistics
include; univariate, bivariate and
multivariate analysis. For instance, "Is
there a relationship between salt intake
and diastolic blood pressure among
middle-age women?" is a problem
definition suitable for analysis by
associative statistics.
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9. 3. Inferential statistics seek to assess
the characteristics of a sample in
order to make more general
statements about the parent
population, or about the relationship
between different samples or
populations.
• Measures of differences of the means
and measures of statistical significance
• For Example; "Does a low sodium diet
lower the diastolic blood pressure of
middle-age women?" represents a
problem definition suitable for inferential
statistics.
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10. ISSUES TO CONSIDER IN DATAANALYSIS
• There are a number of issues to consider
with respect to data analysis. These
include:
• Having the necessary skills to analyze
• Following acceptable norms for data analysis and
presentation
• Choosing the appropriate statistical software
• Providing honest and accurate analysis
• Manner of presenting data
• Extent of data analysis
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11. AStatistical package is a computer programme
that specializes in statistical data analysis.
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12. ROLE OF STATISTICAL SOFTWARES IN DATA
ANALYSIS
• Input data into the computer
• Organise data
• Compare data
• Manage data
• Summarise data (transform raw data into information)
• Generate tables and graphs
• Facilitate presentation of information and preparation of
analytical reports
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13. ISSUES TO CONSIDER WHEN CHOOSING A
STATISTICAL PACKAGE
• Important to know more than one statistical software
package
• Analyse your needs with respect to data management
and analysis; and choose a package that addresses the
needs
• Ease of importing and exporting data to other computer
programmes
• Ease of transferring the output into word processing
facilities
• General Vs Specialized purpose statistical software
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15. SPSS interface
• Data view
• The place to enter data
• Columns: variables
• Rows: records
• Variable view
• The place to enter variables
• List of all variables
• Characteristics of all variables
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16. Variables
• A variable is any characteristic to be measured that
varies from one individual member of the population
to another. Every question on the questionnaire is a
variable.
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17. Example of Variable
• Considering human in a study; variables
include:
• Age,
• Height,
• Sex,
• Weight,
• Location
• Race, etc.
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18. Types of Scales
• Nominal- objects or people are categorized
according to some criterion (gender, job
category)
• Ordinal- Categories which are ranked
according to characteristics (income- low,
moderate, high)
• Scale - contain numerical measures. They
are solely quantitative.
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19. Types of Data
• A data set may contain a mixture of several data
types.
• These data types may be broadly classified as
either string, categorical or numerical data.
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20. Categorical Data
• These data have values that are described by words rather than
numbers. They are also called qualitative data.
• Examples include
• Data on marital status of students (single, married, divorce);
• Sex distribution data of lecturers in Ghana (males, females).
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21. Numerical Data
• Data arise from counting, measuring something, or from some
kind of mathematical operation
• It is called quantitative data
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23. Before you can enter the information from your
questionnaire, interviews or experiment into
SPSS it is necessary to prepare a ‘codebook’.
This is a summary of the instructions you will use
to convert the information obtained from each
subject or case into a format that SPSS can
understand.
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24. •Preparing the codebook involves
deciding (and documenting) how you
will go about:
1. defining and labelling each of the
variables;
2. assigning numbers to each of the
possible responses.
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25. NOTE!!
•All this information should be
recorded in a book or computer
file. Keep this somewhere safe;
there is nothing worse than
coming back to a data file that you
haven’t used for a while and
wondering what the abbreviations
and numbers refer to.
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26. EXAMPLE OF CODEBOOK
Variable SPSS Variable name Coding instructions
SEX SEX 1=FEMALE
2=MALE
MARITAL STATUS MARITAL 1=MARRIED
2=SINGLE
3=DIVORCED
4=WIDOWED
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29. •Each response must be assigned
a numerical code before it can be
entered into SPSS. Some of the
information will already be in this
format (e.g. age in years), other
variables such as sex will need to
be converted to numbers (e.g.
1=males, 2=females).
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30. Example question
• What is your current marital status? (please tick)
Single
In a relationship
Married
Divorced
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31. •To code responses to the question
above: if a person ticked single,
they would be coded as 1; if in a
relationship, they would be coded
2; if married, 3; and if divorced, 4
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33. • For open-ended questions (where
respondents can provide their own
answers), coding is slightly more
complicated.
• Example: What is the major source of
your income?
• To code responses to this you will need to
scan through the questionnaires and look
for common themes. You might notice a lot
of respondents listing their source of
income.
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34. • In your codebook you list these major groups of
responses under the variable name stress, and
assign a number to each (work=1, finances=2
and so on).
• You also need to add another numerical code for
responses that did not fall into these listed
categories (other=value).
• When entering the data for each respondent you
compare his/her response with those listed in the
codebook and enter the appropriate number into
the data set under the variable name you give.
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35. • Once you have drawn up your codebook,
you are almost ready to enter your data.
There are two things you need to do first:
1. Get to know SPSS, how to open and
close files, become familiar with the
various ‘windows’ and dialogue boxes
that it uses.
2. Set up a data file, using the information
you have prepared in your codebook
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37. •Before you can enter your data,
you need to tell SPSS about
your variable names and
coding instructions.
•This is called ‘defining the
variables’
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38. • Name
In this column, type in the variable name that will
be used to identify each of the variables in the
data file. These should be listed in your
codebook.
• .
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39. Rules for naming of variables
• Variable names: must be unique (i.E. Each variable in a data set must
have a different name);
• Must begin with a letter (not a number);
• Cannot include full stops, blanks or other characters (!, ? * ‘’);
• Cannot include words used as commands by SPSS (all, ne, eq, to, le,
lt, by, or, gt, and, not, ge, with); and
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40. • Type
• The default value for Type that will appear
automatically as you enter your first
variable name is Numeric. For most
purposes this is all you will need to use.
There are some circumstances where other
options may be appropriate
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41. • Width
The default value for Width is 8. This is usually sufficient for
most data. If your variable has very large values you may
need to change this default value, otherwise leave it as is.
Decimals
The default value for Decimals (which I have set up using
the Options facility described earlier in this chapter) is 0. If
your variable has decimal places, change this to suit your
needs. If all your variables require decimal places, change
this under Options (using the Data tab). This will save you
a lot of time manually changing each of the variables.
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42. • Label
The Label column allows you to provide a longer
description for your variable than the eight
characters that are permitted under the Variable
name. This will be used in the output generated
from the analyses conducted by SPSS.
Values
In the Values column you can define the meaning
of the values you have used to code your
variables. I will demonstrate this process for the
variable ‘Sex’.
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43. 1. Click on the three dots on the right-hand side of the cell.
This opens the Value Label dialogue box.
2. Click in the box marked Value. Type in 1.
3. Click in the box marked Value Label. Type in Male.
4. Click on Add. You will then see in the summary box:
1=Male.
5. Repeat for Females: Value: enter 2, Value Label: enter
Female. Add.
6. When you have finished defining all the possible values
(as listed in your codebook),
click on Continue.
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44. • Missing
Sometimes researchers assign specific values to indicate
missing values for their data. This is not essential—SPSS
will recognise any blank cell as missing data. So if you
intend to leave a blank when a piece of information is not
available, it is not necessary to do anything with this
Variable View column.
Columns
The default column width is usually set at 8. This is
sufficient for most purposes— change it only if necessary
to accommodate your values. To make your data file
smaller (to fit more on the screen), you may choose to
reduce the column width. Just make sure you allow
enough space for the width of the variable name.
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45. • Measure
The column heading Measure refers to the level of
measurement of each of your variables. The
default is Scale, which refers to an interval or
ratio level of measurement. If your variable
consists of categories (e.g. sex), then click in the
cell, and then on the arrow key that appears.
Choose Nominal for categorical data, and Ordinal
if your data involve rankings, or ordered values.
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46. Opening an existing data file
• If you wish to open an existing data file
click on File from the menu across the top
of the screen, and then choose Open, and
then Data. The Open File dialogue box
will allow you to search through the various
directories on your computer to find where
your data file is stored.
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47. • There are a number of different ways to start
SPSS:
• The simplest way is to look for an SPSS icon on
your desktop. Place your cursor on the icon and
double-click.
• You can also start SPSS by clicking on Start,
move your cursor up to Programs, and then
across to the list of programs available. Move up
or down until you find SPSS for Windows.
• SPSS will also start up if you double-click on an
SPSS data file listed in
• Windows Explorer—these files have a .sav
extension.
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48. CAUTION
•You should always open data
files from the hard drive of your
computer, not the Floppy or A:
drive. If you have data on a
floppy disk, transfer it to a
folder on the hard drive of your
computer before opening it.
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49. Saving a data file
• Remember to save your data file. This does
not happen automatically, as in some word
processing programs. If you don’t save
regularly, and there is a power blackout or
you accidentally press the wrong key, you
will lose all of your work. So save yourself
the heartache and save regularly. If you are
entering data, this may need to be as often
as every ten minutes or after every five or
ten questionnaires.
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50. •To save a file you are working on,
go to the File menu (top left-hand
corner) and choose Save. Or, if
you prefer, you can also click on
the icon that looks like a floppy
disk, which appears on the toolbar
at the top, left of your screen.
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51. CREATING A DATA FILE
AND ENTERING DATA
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52. Process
Step 3. Enter the data—that is, the values obtained
from each participant or respondent for each
variable.
Step 2. Set up the structure of the data file by
‘defining’ the variables.
Step 1. Check and modify, where necessary, the
options that SPSS uses to display the data and the
output that is produced.
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54. From the menus, choose:
Data
Define Multiple Response Sets
Select two or more variables. If your variables are coded
as dichotomies, indicate which value you want to have
counted.
Enter a unique name for each multiple response set. The
name can be up to 63 bytes long. A dollar sign is
automatically added to the beginning of the set name.
Enter a descriptive label for the set. (This is optional.)
Click Add to add the multiple response set to the list of
defined sets.
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56. Computing Variables
• Use the Compute dialog box to compute values for a
variable based on numeric transformations of other
variables.
• „You can compute values for numeric or string
(alphanumeric) variables.
• „You can create new variables or replace the values of
existing variables. For new variables, you can also specify
the variable type and label.
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57. • From the menus choose:
• Transform
• Compute Variable
• Type the name of a single target variable. It can be an
existing variable or a new variable to be Added to the
active dataset.
• To build an expression, either paste components into the
Expression field or type directly in the Expression field.
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59. Procedure for entering data
1. To enter data you need to have the Data View active. Click
on the Data View tab at the bottom left-hand side of the
screen. A spreadsheet should appear with your newly
defined variable names listed across the top.
2. Click on the first cell of the data set (first column, first row). A
dark border should appear around the active cell.
3. Type in the number (if this variable is ID this should be 1, that
is case or questionnaire number 1).
4. Press the right arrow key on your keyboard; this will move the
cursor into the second cell, ready to enter your second piece of
information for case number 1
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60. 5. Move across the row, entering all the information for
case 1, making sure that the values are entered in the
correct columns.
6. To move back to the start, press the Home key on your
keypad. Press the down arrow to move to the second row,
and enter the data for case 2.
7. If you make a mistake and wish to change a value: Click
in the cell that contains the error. The number will appear
in the section above the table. Type the correct value in
and then press the right arrow key.
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62. •Data files can be prepared in
the Microsoft Excel program
and then imported into
SPSS for analysis.
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63. • Step 1: Set up the variable names.
Set up an Excel spreadsheet with the variable names in
the first row across the page. The variable names must
conform to the SPSS rules for naming variables.
• Step 2: Enter the data
Enter the information for the first case on one line across
the page, using the appropriate columns for each
variable. Repeat for each of the remaining cases. Click on
File, Save. In the section marked Save as Type make
sure ‘Microsoft Excel Workbook’ is selected. Type in an
appropriate file name.
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64. • Step 3: Converting to SPSS format
• After you have entered the data, save your file
and then close Excel. Start SPSS and, with the
Data Editor open on the screen, click on File,
Open, Data, from the menu at the top of the
screen. In the section labelled Files of Type
choose Excel. Excel files have a .xls extension.
Find the file that contains your data. Click on it so
that it appears in the File name section. Click on
the Open button. A screen will appear labelled
Opening Excel Data Source. Make sure there is a
tick in the box: Read variable names from the first
row of data. Click on OK.
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65. • Step 4: Saving as an SPSS file
• When you have completed this process of fully
defining the variables, you need to save your file
as an SPSS file. Choose File, and then Save As
from the menu at the top of the screen. Type in a
suitable file name. Make sure that the Save as
Type is set at SPSS (*.sav). Click on Save. When
you wish to open this file later to analyse your
data using SPSS, make sure you choose the file
that has a .sav extension (not your original Excel
file that has an .xls extension).
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66. Summary
Set up the
variable names
• 1
Enter the data
• 2
Convert to
SPSS format
• 3
Save as an
SPSS file
• 4
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68. •Before you start to analyse your
data it is essential that you check
your data set for errors. It is very
easy to make mistakes when
entering data, and unfortunately
some errors can completely mess
up your analyses. For example,
entering 35when you mean to
enter 3 can distort the results.
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69. The data screening process involves
a number of steps:
Step 1:
Checking for errors. First, you need to check each of your variables for
scores that are out of range (i.e. not within the range of possible scores).
Step 2:
Finding the error in the data file. Second, you need to find where in the
data file this error occurred (i.e. which case is involved).
Step 3:
Correcting the error in the data file. Finally, you need to correct the error in
the data file itself.
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70. Checking for errors
• When checking for errors you are primarily looking for
values that fall outside the range of possible values for a
variable. For example, if sex is coded 1=male, 2=female,
you should not find any scores other than 1 or 2 for this
variable.
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71. • To check for errors you will need to inspect the
frequencies for each of your variables. This includes all of
the individual items that make up the scales.
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72. Procedure for checking categorical
variables
1. From the main menu at the top of the screen click on:
Analyze, then click on Descriptive Statistics, then
Frequencies.
2. Choose the variables that you wish to check (e.g. sex,
marital, educ.).
3. Click on the arrow button to move these into the
variable box.
4. Click on the Statistics button. Tick Minimum and
Maximum in the Dispersion section.
5. Click on Continue and then on OK.
The output generated using this procedure is displayed
below (only selected output is displayed).
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75. • Once you are sure there are no errors in the data
file (or at least no out-of-range values on any of
the variables), you can begin the descriptive
phase of your data analysis.
• Descriptive statistics have a number of uses.
These include:
To describe the characteristics of your sample in
the method section of your report;
To check your variables for any violation of the
assumptions underlying the statistical techniques
that you will use to address your research
questions; and
To address specific research questions.
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76. Categorical variables
• To obtain descriptive statistics for categorical variables
you should use Frequencies.
• This will tell you how many people gave each response
(e.g. how many males, how many females).
• It doesn’t make any sense asking for means, standard
deviations etc. for categorical variables, such as sex or
marital status.
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77. Descriptive Statistics
• Descriptive statistics have a number of uses. These
include:
• to describe the characteristics of your sample in the
Method section of your report;
• to check your variables for any violation of the
assumptions underlying the statistical techniques that you
will use to address your research questions; and
• to address specific research questions.
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78. Frequencies (mostly for categorical
variables)
• Analyze, then click on
• Descriptive Statistics,
• Frequencies.
• Select the categorical variables you are
interested in (e.g. sex) and move them into the
Variables box.
• Click on the Statistics button. In the Dispersion
section tick Minimum and Maximum.
• Click on Continue and then OK.
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79. Descriptive (mostly for continuous
variables)
• Analyze, then click on
• Descriptive Statistics,
• Descriptives.
• Select all the continuous variables that you wish to obtain
descriptive statistics
• Click on the arrow button to move them into the Variables
box (e.g. age).
• Click on the Options button.
• Click on mean, standard deviation, minimum,
• maximum,
• Click on Continue, and then OK
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81. • It gives a detailed descriptive analysis of the variables. It
presents a number of information about the variables.
• It provides results for:
Mean
Median
Variance
Percentile
Kurtosis
Skewness
Etc..
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83. • Analyze, then click on
• Descriptive Statistics,
• Cross tabs.
• Select the categorical variables you are
interested in (e.g. sex) and move them into the
Variables boxes.
• Click on the Statistics button. In the Dispersion
section tick Minimum and Maximum.
• Click on Continue and then OK.
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85. Associative Statistics
• Associative statistics seek to identify meaningful
interrelationships between or among data. Such statistics
include; univariate, bivariate and multivariate analysis. It
focus is on detecting and describing relationships among
variables. These techniques can be used to:
explore the association between pairs of variables
predict scores on one variable from scores on another
variable (bivariate regression);
predict scores on a dependent variable from scores of a
number of independent variables (multiple regression);
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88. •Correlation is used when you wish to
describe the strength and direction of
the relationship between two variables
(usually continuous). It can also be
used when one of the variables is
dichotomous—that is, it has only two
values (e.g. sex: males/females).
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89. • Partial correlation is used when you wish to
explore the relationship between two
variables while statistically controlling for a
third variable. This is useful when you
suspect that the relationship between your
two variables of interest may be influenced,
or confounded, by the impact of a third
variable..
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90. •Partial correlation statistically
removes the influence of the third
variable, giving a cleaner picture of
the actual relationship between
your two variables
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91. Summary of bivariate correlation.
Example of
research
question:
Is there a relationship between the
amount of control people have over
their internal states and their levels of
perceived stress?
What you
need:
Two variables: both continuous, or one
continuous and the other categorical.
What it does Correlation describes the relationship
between two variables, in terms of both the
strength of the relationship and the
direction.
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92. Analyze,
Correlate,
Bivariate
Select your variables and move them into
the box marked as variables.
Check that the Pearson box and the 2 tail
box have a cross in them. The two-tail test of significance
means that you are not making any specific prediction concerning the direction
of the relationship between the variables (positive/negative). You can choose a
one-tail test of significance if you have reasons to support a specific direction.
Click OK
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93. Summary of partial correlation.
Example of
research
question:
After controlling for age, is there still a significant
relationship between perceived control of internal
states (PCOISS) and levels of perceived stress?
What you need: three variables: all continuous;
• two variables that you wish to explore the relationship
between (e.g. total PCOISS, total perceived stress); and
• one variable that you wish to control for (age)
What it does It allows you to explore the relationship between two
variables, while statistically controlling for (getting rid of)
the effect of another variable that you think might be
contaminating or influencing the relationship
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94. Analyze,
Correlate,
Partial
Click on the two continuous variables that
you want to correlate.
Click on the variable that you wish to control
for (e.g. age) and move into the Controlling
box.
Choose whether you want one-tail or two-tail
significance
Check that the Pearson box and the 2 tail
box have a cross in them.
Click OK
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95. NOTE
• Pearson product-moment coefficient is designed for
interval level (continuous) variables. It can also be used if
you have one continuous variable and one dichotomous
variable
• Spearman rank order correlation (designed for use with
ordinal level or ranked data)
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97. • Multiple regression is not just one technique but a
family of techniques that can be used to explore
the relationship between one continuous
dependent variable and a number of independent
variables or predictors (usually continuous).
Multiple regression is based on correlation, but
allows a more sophisticated exploration of the
interrelationship among a set of variables. It can
tell you how well a set of variables is able to
predict a particular outcome.
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98. Types
• Linear – between two variables (1 independent variable, 1
dependent variable)
• Multiple between more than two variables (2 or more
independent variables, 1 dependent variable)
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99. Summary of partial correlation.
Example of
research
question:
What is the impact of feeding practices on child
growth
What you need: One continuous dependent variable; and
One, Two or more continuous independent
variables
What it does Multiple regression tells you how much of the
variance in your dependent variable can be
explained by your independent variables. It also
gives you an indication of the relative contribution
of each independent variable.
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100. Analyze, then click on
Regression, then on
Linear.
Click on your continuous dependent variable and move it
into the Dependent box.
Click on your independent variables and move them into
the Independent box.
For Method, make sure Enter is selected (this will give you
standard multiple regression).
Click on OK
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