Quiz (Chapter 2)

Descriptive Statistics

Picture Techniques for Summarizing Data
1. If you add all the numbers in the "f" column of an ungrouped frequency distribution, you'll get ___ .
 F M N R
2. In Excerpt 2.1, what is the cumulative frequency for TAS scores up to and including 2?
 4 3.8 11 70
3. How many scores are being summarized in this row of a stem-and-leaf display: 6|1129
 4 5 1,129 61,129
4. What determines the height of each "bar" in a histogram?
 N f M R
5. The technical names for the horizontal and vertical axes in a bar graph or line graph are ____and ____ , respectively.
 abscissa; ordinate ordinate; abscissa
6. "Frequency polygon" is to "line graph" as "_____" is to "bargraph."
 Bar polygon Polybar Histograph Histogram
7. Which of the following techniques for summarizing data is characterized by "loss of information?"
 Grouped frequency distribution Ungrouped frequency distribution Stem-and-leaf display
8. In Excerpt 2.5, what are the compliance scores summarized on the bottome row of the stem-and-leaf display?
 0 and 4 20 and 40 20 and 24 200 and 204
Distributional Shape
1. A normal distribution is often said to be "___-shaped."
 bell carrot cigar fish
2. 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.
 True False
3. What kind of skewness is associated with the data shown in Excerpt 2.4?
 Positive skewness Negative skewness Absolutely no skewness at all It's impossible to tell
4. Based on the information presented in Excerpt 2.9, the "extreme" scores were _____ .
 low high
5. Compared to a normal distribution, a __________ distribution is "tall and skinny" whereas a _________ distribution is "low and flat."
 leptokurtic; platykurtic platykurtic; leptokurtic
6. What are the numerical values for skewness and kurtosis for a symmetrical mesokurtic distribution?
 0 and 0 1 and 1 10 and 10 100 and 100
Measures of Central Tendency
1. In the field of statistics, the term "average" is used to signify only the mean.
 True False
2. Which measure of central tendency gives the "middle score" (or "mid-point")?
 Mean Median Mode
3. If the largest of these 7 scores [14, 4, 10, 8, 6, 12, 16] is changed from 16 to 86, the mean will double in size while the median remains unchanged.
 True False
4. Which measure of central tendency assumes the highest score (along the baseline) in skewed distributions?
 Mean Median Mode It depends on what kind of skewness exists
5. Which of these symbols is sometimes used to signify the mean?
 a b m s
6. If the mean, median, and mode are 50, 60, and 70, respectively, what kind of skewness exists in the data?
 Positive skewness Negative skewness It is impossible to know
Measures of Variability
1. 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 ____ variability in the data from all 136 participants.
 more less
2. How many quartile points are there, and which one has the largest numerical value?
 3; Q1 3; Q3 4; Q1 4; Q4
3. What is the name for the numerical distance between the 75th and 25th percentiles?
 Interquartile range Semi-interquartile range
4. For these data [9, 1, 6, 5, 4, 7, 2, 5], what is the semi-interquartile range equal to?
 1.75 3.50 4.00 8.00 9.50
5. The semi interquartile range is always equal to one-half the distance between Q1 & Q3.
 True False
6. In Excerpt 2.21, the middle 50 percent of the 32 pain scores at baseline were between ___ and ___ .
 4 and 8 4 and 10 2 and 4 2 and 8 2 and 10
7. Researchers rarely report both the SD and the variance for the same data set.
 True False
8. In Excerpt 2.26, the variance of the Digit Span scores was equal to about __.
 1.4 2 4 5.80 9
9. If all of the scores are negative, the SD itself will turn out to be a negative value.
 True False
10. One symbol for the variance is s2; another symbol for the variance is ___.
 s s2 s2
11. Based on the information in Excerpt 2.24, we should guess that the oldest young adult was about ___ years older than the youngest young adult.
 2 4 9 20 30
12. If a researcher summarizes his/her data by saying  38 ± 12, what does the 12 indicate?
 The mean The median The mode The standard deviation The variance
13. 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 ___.
 .05 .5 2.0 20.0
Standard Scores
1. If you took a test, your standard score would indicate how many standard deviations you ended up away from the _____.
 high score low score mean median mode
2. Whereas a z-score of +1.5 is equal to a T-score of  __, a T-score of 48 is equal to a z-score of __.
 51.5; -2.0 51.5; 4.8 65; -2.0 65; 4.8 None of the above
3. Based on the information in Excerpt 1.9 (in Chapter 1), one of thestudents who self-reported having a "B" GPA would have had a Locus of Control score of 18.7 if his/her T-score was equal to 60.
 True False
A Few Cautions
1. Researchers sometimes use the term "skewed" to mean something other than "positively skewed" or "negatively skewed."
 True False
2. 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.
 True False
3. A score in a data set that lies far away from the rest of the scores is called a(n)_____.
 blip grub outlier skewtoid troublemaker
4. In Excerpt 2.35, a rule for identifying outliers is articulated. If that rule had been applied to the 6-month data in Excerpt 2.21, would there have been any outliers?
 Yes No