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1. Central Tendency and Probability
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Attachment PreviewWeek 2 Practice Worksheet PSY/315 Version 7 University of Phoenix
Material Week 2 Practice Worksheet Provide a response to the following questions. 1. The
Wilcox & Keselman (2003) article from this week’s electronic readings discusses two
problems with measures of central tendency: skewness of the data and outliers. Discuss
each of these issues and how they affect measures of central tendency. 2. For the following
scores, find the mean, median, and mode. Which would be the most appropriate measure
for this data set? You may use Microsoft® Excel® data anlysis to compute these statistics.
You may copy your output from Microsoft® Excel® into this worksheet. 2, 2, 0, 5,1, 4,1, 3, 0,
0, 1, 4, 4, 0,1, 4, 3, 4, 2, 1 3. Based on the scale of measurement for each variable listed
below, which measure of central tendency is most appropriate for describing the data? a.
The time (in years) it takes a sample of students to graduate college. b. The blood type (such
as A, B, AB, or O) of a group of participants. c. The rankings of college undergraduate
academic programs. 4. How do the sample mean and the population mean differ? What is
the symbol for each type of mean? 5. An expert reviews a sample of 10 scientific articles (n =
10) and records the following numbers of error in each article: 0, 4, 2, 8, 2, 3, 1, 0, 5, and 7.
Compute the SS, the variance, and the standard deviation for this sample using the
definitional and computational formulas. You may use Microsoft® Excel® data anlysis to
compute these statistics. You may copy your output from Microsoft® Excel® into this
worksheet. 6. A psychologist interested in political behavior measured the square footage of
the desks in the official office of four U.S. governors and of four CEOs of major U.S.
corporations. The figures for the governors were 44, 36, 52, and 40 square feet. The figures
for the CEOs were 32, 60, 48, 36 square feet. a. Figure the means and standard deviations
for the each group: governors and CEOs. b. Explain, to a person who has never had a course
in statistics, what you have done. c. Note the ways in which the means and standard
deviations differ, and speculate on the possible meaning of these differences, presuming
they are representative of U.S. governors and large corporations’ CEOs in general. Central
Tendency and Probability7. Radel and colleagues (2011) conducted a study of how feeling
overly controlled makes you desire— Copyright © 2016, 2014 by University of Phoenix. All
rights reserved. 1 Week 2 Practice Worksheet PSY/315 Version 7 even unconsciously—
more freedom. In their study, 52 Canadian undergraduates played a video game in a

2. laboratory and were randomly assigned to one1 of the following: • • An automony
deprivation condition, in which they were told to follow instructions precisely, constantly
given instructions over a loudspeaker, and carefully observed on everything they did. A
neutral condition, which was much more laid back. After this activity, they were asked to do
a lexical decision task (a standard approach for measuring unconscious responses), in
which they were shown a series of words and nonwords in random order and had to press
C if it was a real word or N if not. Half of the real words were related to autonomy (such as
freedom and choice), and half were neutral (such as whisper and hammer). The key focus of
the study was on how long it took people to press the button (response latency) for each
kind of real word, averaged over the many words of each type. The table below shows the
mean and standard deviation across the participants of these four categories of results. For
example, 782 milliseconds (thousandths of a second) is the average time it took participants
in the autonomy-deprived condition to respond to the autonomy-related words, and 211 is
the standard deviation across the 26 participants’ average response time in that condition.
Explain the numbers in this table to a person who has never taken a course in statistics. (Be
sure to explain some specific numbers, as well as the general principle of the mean and
standard deviation.) For your interest, the pattern of results shown here supported the
researchers’ hypothesis: “Relative to a neutral instructional climate, a controlling climate
thwarting the need for autonomy…enhanced accessibility for autonomy-related words” (p.
924). Mean Latencies (in Milliseconds) in the Lexical Task Assessing Accessibility for
Autonomy-Related Constructs (Experiment 1) Condition Autonomy Deprivation Construct
Neutral M SD M SD Autonomy-related words 782 211 857 243 Neutral words 835 258 841
301 8. A researcher records the levels of attraction for various fashion models among
college students. He finds that mean levels of attraction are much higher than the median
and the mode for these data. a. What is the shape of the distribution for the data in this
study? b. What measure of central tendency is most appropriate for describing these data?
Why? 9. An organizational psychologist measures levels of job satisfaction in a sample of 30
participants. To measure the variance of job satisfaction, it is calculated that the SS = 120 for
this sample. a. What are the degrees of freedom for the variance? b. Compute the variance
and standard deviation (you will have to do this one by hand). 10. State the three empirical
rules for a normal distribution with any mean and varaince. Copyright © 2016, 2014 by
University of Phoenix. All rights reserved. 2 …Central Tendency and Probability