2. Statistics...
A set of mathematical procedures for
describing, synthesizing, analyzing,
and interpreting quantitative data.
…the selection of an appropriate
statistical technique is determined by
the research design, hypothesis, and
the data collected
3. Preparing data for analysis...
Data must be accurately scored and
systematically organized to facilitate
data analysis:
tabulating: organizing the data in a
systematic manner
coding: assigning numerals (e.g., ID)
to data
scoring: assigning a total to each
participant’s instrument
18. quartile deviation...
…one half of the difference between
the upper quartile (the 75%’ile) and
the lower quartile (the 25%’ile) in a
distribution
19. variance...
…a summary statistic indicating the
degree of variability among
participants for a given variable
20. standard deviation...
…the square root of variance providing
an index of variability in the
distribution of scores
21. Normal distributions of data
(the normal curve)...
A bell-shaped distribution of scores
having four identifiable properties…
…50% of the scores fall above the
mean and 50% of the scores fall
below the mean
…the mean, median, and mode are the
same value
22. …most scores are near the mean and,
the farther from the mean a score is,
the fewer the number of participants
who attained that score
…the same number, or percentage, of
scores is between the mean and plus
one standard deviation as is between
the mean and minus one standard
deviation
23. Non-normal distributions of data
(skewed distributions)...
A non-bell-shaped distribution of scores
where…
…mean < median < mode
(a “negatively skewed distribution”)
…mean > median > mode
(a “positively skewed distribution”)
24. measures of relative position...
…indices enabling the researcher to
describe a participant’s performance
compared to the performance of all
other participants
25. 4. Measures of relative position…
percentile ranks
standard scores
34. correlations
…determines whether and to what
degree a relationship exists between
two or more quantifiable variables
…the degree of the relationship is
expressed as a coefficient of
correlation
35. …the presence of a correlation does
not indicate a cause-effect
relationship primarily because of the
possibility of multiple confounding
factors
38. Pearson r...
…a measure of correlation used for
data of interval or ratio scales
…assumes that the relationship
between the variables being
correlated is linear
39.
40. Mini-Quiz…
True and false…
…the analysis of the data is as
important as any other component
of the research process
True
41. True and false…
…descriptive statistics are normally
computed separately for each
group in a research study
True
42. True and false…
…every instrument administered
must always be scored accurately
and consistently, using the same
procedures and criteria
True
43. True and false…
…tentative scoring procedures must
always be tried out beforehand by
administering the instrument to the
study participants
False
44. True and false…
…a computer should not be used to
perform an analysis that a
researcher has never completed by
hand or, at least, studied
extensively
True
45. True and false…
…the first step in data analysis is to
describe, or summarize, the data
using descriptive statistics
True
46. True and false…
…the number resulting from the
computation of a measure of central
tendency represents the typical
score attained by a group of
participants
True
47. True and false…
…the mean is the most precise,
stable index of typical performance
that is especially useful in
situations in which there are
extreme scores
False
48. True and false…
…unless a correlation coefficient is
used to compute the reliability of
an instrument in a causal-
comparative or experimental study,
a correlation coefficient is only
computed in a correlation study
True
49. True and false…
…plus and/or minus two standard
deviations includes more the 99%
of the scores
False
50. True and false…
…standard scores are rarely used in
research studies
True
51. True and false…
…to test a hypothesis adequately,
more than descriptive statistics are
normally needed
True
52. True and false…
…if the extreme scores are at the
upper, or higher, end of the
distribution, it is said to be
positively skewed
True
53. True and false…
…the median of a set of scores
corresponds to the 50% percentile
True
54. True and false…
…a standard score is a measure of
relative position that is appropriate
when the data represent a nominal
scale
False
55. True and false…
…a z score expresses how far a
score is from the mean in terms of
standard deviation units
True
56. True and false…
…the Spearman Rho is the
appropriate measure of correlation
when the variables are expressed
as ranks instead of scores
True
57. True and false…
…the assumption associated with the
application of Pearson r is that the
relationship between the variables
being correlated is linear
True
58. Fill in the blank…
…statistics which permit the
researcher to describe many scores
with a small number of indices
descriptive statistics
59. Fill in the blank…
…the values calculated for a sample
drawn form a population
statistics
60. Fill in the blank…
…the values calculated for an entire
population
parameters
61. Fill in the blank…
…a convenient way to describe a set of
data with a single number
measures of central tendency
62. Fill in the blank…
…the index of central tendency
appropriate for nominal data
mode
63. Fill in the blank…
…the index of central tendency
appropriate for ordinal data
median
64. Fill in the blank…
…the index of central tendency
appropriate for interval or ratio data
mean
65. Fill in the blank…
…the score attained by more
participants than any other score
mode
66. Fill in the blank…
…the point in a distribution above and
below which are 50% of the scores
median
67. Fill in the blank…
…the arithmetic average of the scores
mean
68. Fill in the blank…
…the difference between the highest
and lowest score in a distribution
range
69. Fill in the blank…
…the measure of variability identifying
one half of the difference between
the 75th percentile and the 25th
percentile
quartile deviation
70. Fill in the blank…
…the measure of variability used for
interval and ratio data
standard deviation
71. Fill in the blank…
…the only appropriate measure of
variability for nominal data
range
72. Fill in the blank…
…+/- 1.00 standard deviations
constitutes ____ % of the sample
68%
73. Fill in the blank…
…extreme scores at the lower end of
the distribution indicates a ______
skewed distribution
positively
74. Fill in the blank…
…indices describing where a score is
in relation to all other scores
measures of relative position
75. Fill in the blank…
…indicates the percentage of scores
that fall at or below a given score
percentile ranks
76. Fill in the blank…
…if a set of scores is transformed into
a set of z scores, the new
distribution has a mean of ____ and
a standard deviation of ____
zero; one
77. Fill in the blank…
…a set of standard scores that divide a
distribution into nine parts
stanines
78. Fill in the blank…
…the most appropriate measure of
correlation when the sets of data to
be correlated represent either
interval or ratio scales
Pearson r
79. This module has focused on...
descriptive statistics
...the statistical procedures for
describing, synthesizing, analyzing,
and interpreting quantitative data
80. The next module will focus on...
...the statistical procedures for
generalizing to a population of
individuals based on information
obtained from a limited number of
research participants
inferential statistics