Quiz (Chapter 2)
Descriptive Statistics
Picture Techniques for Summarizing Data
 If you add all the numbers in the "f" column of an ungrouped frequency
distribution, you'll get ___ .
 In Excerpt 2.1, what is the cumulative frequency for TAS scores
up to and including 2?
 How would you interpret this if it were presented in a stemandleaf
display: 61129
 What determines the height of each "bar" in a histogram?
 N
 f
 M
 r
 R
 The technical names for the horizontal and vertical axes in a bar
graph or line graph are ____ and ____ , respectively.
 "Frequency polygon" is to "line graph" as "_____" is to "bargraph."
 When raw scores are summarized via a grouped frequency distribution,
is there "loss of information?" What about when raw scores are
summarized via a stemandleaf display?
 In Excerpt 2.5, what are the compliance scores summarized on the
bottom row of the stemandleaf display?
Distributional Shape
 A normal distribution is often said to be "___shaped."
 (T/F) In Excerpt 2.6, the histrogram would have more closely
resembled a normal distribution if there had been 18 individuals with
a Rotter
score of 12.
 What kind of skewness is associated with the data shown in Excerpt
2.4?
 Based on the information presented in Excerpt 2.9, the "extreme"
scores were _____ (high/low).
 What does a leptokurtic distribution look like? A platykurtic
distribution?
 What are the numerical values for skewness & kurtosis for a symmetrical
mesokurtic distribution?
Measures of Central Tendency
 (T/F) In the field of statistics, the term "average" is used to signify
only the mean.
 Which measure of central tendency gives the "middle score" (or "midpoint")?
 What's the median & mean for: 14, 4, 10, 8, 6, 12, 16?
Change 16 to 86 and reanswer.
 Which measure of central tendency assumes the highest score in skewed
distributions?
 What Greek letter is sometimes used to signify the mean?
 If the mean, median, and mode are 50, 60, and 70, respectively, does
that suggest negative skewness?
Measures of Variability
 In Excerpt 2.6, if the bars over the scores of 3 and 11 had been
reversed and if the bars over the scores of 14 and 20 had been reversed,
there would have been ____ (more/less) variability in the data from
all 136
participants.
 How many quartiles are there? How are they labeled? Which
one is the highest?
 What is the name for the numerical distance between the 75th and
25th percentiles?
 For these data, what is the semi interquartile range equal to?
9, 1, 6, 5, 4, 7, 2, 5
 (T/F) The semi interquartile range is always equal to onehalf the
distance between Q1 & Q3.
 In Excerpt 2.21, the middle 50 percent of the 32 pain scores
at baseline were between ___ and ___ .
 (T/F) Researchers rarely report both the SD and the variance for
the same data set.
 In Excerpt 2.26, the variance of the Digit Span scores was equal
to about ___.
 (T/F) If all of the scores are negative, the SD itself will turn
out to be a negative value.
 One symbol for the variance is s2; another symbol for
the variance is ___.
 (T/F) Based on the information in Excerpt 2.24, we should guess that
the oldest young adult was about 9 years older than the youngest young
adult.
 If a researcher summarizes his/her data by saying 38 ±
12, what does the 12 indicate?
 If a group of scores has a mean equal to 10 and a SD equal to 20,
the coefficient of variation will be equal to ___.
Standard Scores
 A standard score simply indicates the number of ____ between a raw
score and ____.
 A zscore of +1.5 is equal to a Tscore of __. A Tscore of
48 is equal to a zscore of __.
 Based on the information in Excerpt 1.9 (in Chapter 1), one of the
students who selfreported having a "B" GPA would have had a Locus
of Control score of ___ if his/her Tscore
was
equal to 60.
A Few Cautions
 (T/F) Researchers sometimes use the term "skewed" to mean something
other than "positively skewed" or "negatively skewed."
 (T/F) If a researcher uses the term "average" without specifying
whether it's the mean, median, or mode, you'll most likely be correct
if you guess that it's the median.
 A score in a data set that lies far away from the rest of the scores
is called a(n)_____.
 In Excerpt 2.35, a rule for identifying outliers is articulated.
If that rule had been applied to the 6month data in Excerpt 2.21,
would there have been any outliers?
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