Quiz Over Chapter 2 of the 6th Edition

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, how many students exercised vigorously less than 3 days a week?
 75 107 145 238
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 Excerpts 2.4 and 2.5, each vertical bar reveals information about a portion of the collected data by means of the vertical bar's
 width height width and height
Distributional Shape
1. A normal distribution is often said to be "___-shaped."
 bell carrot cigar fish
2. (T/F) In Excerpt 2.6, the distribution of ages would have resembled more closely a normal distribution if 24% of the group had been between the ages of 21-25, with only 8% of the group between the ages of 26-30.
 True False
3. What kind of skewness is associated with the data shown in Excerpt 2.1?
 Positive skewness Negative skewness There is no skewness It's impossible to tell
4. Based on the information displayed in Excerpt 2.7, 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 2.7, if the bars over the scores of 1 and 11 had been reversed, and if the bars over the scores of 1 and 12 had been reversed, there would have been ____ variability among the study's patients.
 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 2.16, what percentage of the participants were between 28 and 59 years old?
 25 50 59 66 71
7. Researchers rarely report both the SD and the variance for the same data set.
 True False
8. In Excerpt 2.20, the variance of the third variable (Number of places slept last week) would be equal to ___.
 1.414 2 4 6.25 It is impossible to determine.
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. If N = 100 and SD = 10, you should guess that the range of scores = ___ .
 5 10 20 50 500
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. Look at Excerpt 2.20, and concentrate on the 3rd variable (Number of places slept last week). If one of the research participants had slept in 5 different places, that participant's z-score would be equal to ___ .
 1.25 2 2.5 4.5 5
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 2.27, a rule for identifying outliers is articulated. If that rule is applied to the age data in Excerpt 2.19, are there any outliers?
 Yes No