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 ___ .
  2. In Excerpt 2.1, what is the cumulative frequency for TAS scores up to and including 2?
  3. How would you interpret this if it were presented in a stem-and-leaf display: 6|1129
  4. What determines the height of each "bar" in a histogram?
    1. N
    2. f
    3. M
    4. r
    5. R
  5. The technical names for the horizontal and vertical axes in a bar graph or line graph are ____ and ____ , respectively.
  6. "Frequency polygon" is to "line graph" as "_____" is to "bargraph."
  7. When raw scores are summarized via a grouped frequency distribution, is there "loss of information?"  What about when raw scores are summarized via a stem-and-leaf display?
  8. In Excerpt 2.5, what are the compliance scores summarized on the bottom row of the stem-and-leaf display?

Distributional Shape
  1. A normal distribution is often said to be "___-shaped."
  2. (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.
  3. What kind of skewness is associated with the data shown in Excerpt 2.4?
  4. Based on the information presented in Excerpt 2.9, the "extreme" scores were _____ (high/low).
  5. What does a leptokurtic distribution look like?  A platykurtic distribution?
  6. What are the numerical values for skewness & kurtosis for a symmetrical mesokurtic distribution?

Measures of Central Tendency
  1. (T/F) In the field of statistics, the term "average" is used to signify only the mean.
  2. Which measure of central tendency gives the "middle score" (or "mid-point")?
  3. What's the median & mean for: 14, 4, 10, 8, 6, 12, 16?  Change 16 to 86 and re-answer.
  4. Which measure of central tendency assumes the highest score in skewed distributions?
  5. What Greek letter is sometimes used to signify the mean?
  6. If the mean, median, and mode are 50, 60, and 70, respectively, does that suggest negative skewness?

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 ____ (more/less) variability in the data from all 136 participants.
  2. How many quartiles are there?  How are they labeled?  Which one is the highest?
  3. What is the name for the numerical distance between the 75th and 25th percentiles?
  4. For these data, what is the semi interquartile range equal to?      9, 1, 6, 5, 4, 7, 2, 5
  5. (T/F) The semi interquartile range is always equal to one-half the distance between Q1 & Q3.
  6. In Excerpt 2.21, the middle 50 percent of the 32 pain scores at baseline were between ___ and ___ .
  7. (T/F) Researchers rarely report both the SD and the variance for the same data set.
  8. In Excerpt 2.26, the variance of the Digit Span scores was equal to about ___.
  9. (T/F) If all of the scores are negative, the SD itself will turn out to be a negative value.
  10. One symbol for the variance is s2; another symbol for the variance is ___.
  11. (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.
  12. If a researcher summarizes his/her data by saying  38 ± 12, what does the 12 indicate?
  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 ___.

Standard Scores
  1. A standard score simply indicates the number of ____ between a raw score and ____.
  2. 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 __.
  3. Based on the information in Excerpt 1.9 (in Chapter 1), one of the students who self-reported having a "B" GPA would have had a Locus of Control score of ___ if his/her T-score was equal to 60.

A Few Cautions
  1. (T/F) Researchers sometimes use the term "skewed" to mean something other than "positively skewed" or "negatively skewed."
  2. (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.
  3. A score in a data set that lies far away from the rest of the scores is called a(n)_____.
  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?

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Schuyler W. Huck
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