**DATA 205 Introductory Analytics (QC)**

**Quiz 2 Chapters 3-4**

Question 1As a measure of central tendency, the mode can be used with?

Answers:

a. ?all of these choices are correct.

b. ?interval-ratio data.

c. ?ordinal data.

d. ?nominal data.

Question 2For ordinal level variables, the most appropriate measure of central tendency is generally

Answers:

a. the mode.

b. the median.

c. the mean.

d. None of the above

Question 3For variables measured at the interval-ratio level, the preferred measure of central tendency would be the

Answers:

a. decile.

b. mean.

c. mode.

d. quartile.

Question 4If a distribution of test scores has a mean of 70 and a median of 63, the distribution has

Answers:

a. a few very low scores.

b. a mode of 67.

c. a positive skew.

d. a negative skew.

Question 5If one has data measured at the interval-ratio level, they can use which measure of central tendency??

Answers:

a. ?mean

b. ?you can use any measure on interval-ratio data

c. ?median

d. ?mode

Question 6If the scores of an even number of cases are arranged from high to low, the median is

Answers:

a. the middle score.

b. the same as the mode.

c. exactly halfway between the two middle values.

d. the average of the highest and lowest scores.

Question 7If you changed ONLY the highest score in a distribution of 5 scores, which of the following measure of central tendency would be affected?

Answers:

a. The mean

b. The median

c. The mode

d. All of the above

Question 8In a campaign debate over the level of prosperity in the state, the incumbent governor says: “average income is $53,000.” His opponent responds “the average citizen earns only $38,000.” Both statements are true. This is possible because

Answers:

a. the opponent is using the mean.

b. the opponent is using the mode.

c. the governor is citing the median.

d. the governor is using the mean.

Question 9 In a small seminar class, there were eight Protestants, four Catholics, three Jews, two Muslims, a Buddhist, and seven students with no religious affiliation (â€œNonesâ€). The mode for this variable is

Answers:

a. undefined since the variable is nominal in level of measurement.

b. Protestant.

c. eight.

d. the same as the median.

Question 10

In any distribution, the mean and the median will have the same value when the distribution is

Answers:

a. symmetrical.

b. positively skewed.

c. negatively skewed.

d. All of the above

Question 11 Income distributions almost always have a positive skew (since there are only a few very wealthy people). Therefore, the preferred measure of central tendency for this variable would be the

Answers:

a. mode.

b. median.

c. mean.

d. None of the above

Question 12 The expression ?(Xi) directs us to find the

Answers:

a. median.

b. middle score.

c. average of the scores.

d. sum of the scores.

Question 13The median cannot be found for variables measured at the nominal level because

Answers:

a. there is no central tendency.

b. the distribution is skewed.

c. the scores cannot be ranked or ordered.

d. all of the cases are representative.

Question 14A “good” measure of dispersion should

Answers:

a. use all scores in a distribution.

b. describe the average or typical deviation of the scores.

c. be easy to calculate and interpret.

d. All of the above

Question 15Measures of dispersion provide information about the

Answers:

a. typical or most common score.

b. size of the sample.

c. variety within the distribution of scores.

d. adequacy of the selection criteria for the sample.

Question 16If a distribution of scores has a mean of 30 and a range of 0

Answers:

a. there is no dispersion in the distribution.

b. the standard deviation is 1.

c. the quartile deviation (Q) is 10.

d. the variance is 30.

Question 17If a variable is interval-ratio in level of measurement, the preferred measure of dispersion would be

Answers:

a. the percentile.

b. the mean.

c. the standard deviation.

d. the range.

Question 18If male and female college students have the same mean GPA but the standard deviation for females is much larger, you may conclude that

Answers:

a. males are smarter than females.

b. there is more variability among female students with respect to GPA.

c. modal GPAs for both groups would be the same.

d. median GPAs for both groups would be the same.

Question 19 One problem with the range (R) as a measure of dispersion is that it

Answers:

a. ignores the most extreme scores.

b. can be used only for nominal level variables.

c. is very difficult to calculate.

d. is based on only the most extreme scores.

Question 20Since computation of the standard deviation requires addition, division, and other mathematical operations, it should be used for

Answers:

a. interval-ratio level variables.

b. non-continuous variables at any level of measurement.

c. nominal level variables.

d. discrete variables only.

Question 21The expression ? instructs us to

Answers:

a. subtract the mean from each score and add up the deviations.

b. subtract every â€œithâ€ score from the mean.

c. sum the scores and then subtract the mean.

d. sum the scores.

Question 22The greater the skew of a distribution of scores,

Answers:

a. the lower the value of the standard deviation.

b. the higher the value of the standard deviation.

c. the lower the value of the range.

d. None of the above: measures of dispersion are not affected by skew.

Question 23Which measure of dispersion is most important and most commonly used in social science research?

Answers:

a. The average deviation

b. The standard deviation

c. The range

d. The median

Question 24Which of the following data sets shows the greatest variability?

Answers:

a. 50, 60, 170

b. 0, 5, 9

c. 31, 33, 35

d. 9, 10, 11

Question 25Your score on the test is the same as the third quartile (Q3). You may conclude that

Answers:

a. your score is ‘typical’ since it is the same value as the median.

b. you scored higher than 75% of the people who took the test.

c. the distribution of the scores is skewed.

d. you scored higher than 25% of the people who took the test.