Ch3 Describing Data With Averages Test Questions & Answers

MULTIPLE‑CHOICE TEST ITEMS

CHAPTER 3

DESCRIBING DATA WITH AVERAGES

3.1 The mode reflects the value

a) of the largest frequency.

b) of the most frequently occurring observation.

c) midway between the largest and smallest observations.

d) of the largest observation.

3.2 For the following observations: 2, 5, 3, 2, 4, 6, 2, 4, the mode equals

a) 2

b) 3

c) 4

d) none of the above.

3.3 The shape of a bimodal distribution has

a) two peaks of exactly equal height.

b) two obvious peaks.

c) two peaks located in the middle of the distribution.

d) two or more peaks.

3.4 The value of the mode identifies

a) the midpoint.

b) the balance point.

c) that which is "fashionable."

d) all of the above

3.5 Which one of the following does not describe the median?

a) splits the distribution into upper and lower halves

b) associated with the 50th percentile

c) represents the value midway between the largest and smallest observations

d) associated with the middle value when observations are ordered from least to most

3.6 The identification of the median becomes increasingly cumbersome with larger sets of unorganized data because

a) data must be ordered from least to most.

b) many different observations occur.

c) more than one value of the median might appear.

d) the value of the median might not be a whole number.

3.7 Find the median for the following observations:

6, 4, 8, 1, 2.

a) 3

b) 4

c) 5

d) 8

3.8 Find the median for the following observations:

29, 54, 43, 38, 40, 71.

a) 21

b) 40.5

c) 41.5

d) 42.5

3.9 Which one of the following is true of the mean?

a) observations must be ordered from least to most before calculating the mean

b) equals some whole number

c) one of the less common averages

d) equals the sum of all observations divided by the number of observations

NOTE: 3.10 - 3.12 require Greek letters.

3.10 The symbol for the sample mean is

a) X

b)

c) Σ

d) n

3.11 The symbol for the population mean is

a) N

b) Σ

c) σ

d) μ

3.12 In the formula for the sample mean (or for the population mean), the symbol Σ represents

a) all observations.

b) the total number of observations.

c) any operation.

d) the operation of summing all observations.

3.13 Which one of the following pairs fails to reflect the relationship between a sample and its population, respectively.

a) students in the first row; students in class

b) spoonful of soup; cupful of soup

c) registered Democrats; registered voters

d) students in college; students in class

3.14 Find the mean for the following observations:

6, 7, 1, 0, 6.

a) 4

b) 5

c) 6

d) 20

3.15 In its role as a balance point, the mean balances

a) the distance of the largest observation against the distance of the smallest observation.

b) the combined distance of all observations above the mean against the combined distance of all observations below the mean.

c) the number of larger observations against the number of smaller observations.

d) all of the above

3.16 Unlike the mode or median, the mean is affected by

a) only those observations that are middle-ranked.

b) only those observations that occur most often.

c) all those observations that are extreme.

d) all observations.

3.17 The sum of the deviations of all observations about the mean equals

a) zero.

b) the value of the mean.

c) the median.

d) the total number of observations.

3.18 You're told that the shape of the distribution of burning times for light bulbs is balanced, with a mean burning time of about 1500 hours. Therefore you can conclude that the median burning time

a) equals about 1500 hours.

b) is more than 1500 hours.

c) is fewer than 1500 hours.

d) could be any of the above.

3.19 To describe the average daily load of clients for psychotherapists working at a mental heath clinic, a spokesperson reports a mean load of 5.2 clients and a median load of 7.5 clients. This implies that, among the staff of psychotherapists,

a) all carry about the same load.

b) a few carry relatively light loads.

c) a few carry relatively heavy loads.

d) a few carry either relatively heavy or relatively light loads.

3.20 When a distribution is skewed, report

a) the median.

b) both the median and mode.

c) both the median and mean.

d) the mean.

3.21 Because it's affected by every observation in the distribution, the mean is particularly sensitive to

a) any extreme observation.

b) large numbers of observations.

c) the large subset of intermediate observations.

d) all of the above

3.22 The distribution of annual incomes for U.S. households is positively skewed. If the Census Bureau reports a median annual income of $57,450, this implies that the mean annual income is

a) about the same.

b) larger.

c) smaller.

d) either larger or smaller, but it's impossible to decide on the basis of the available information.

3.23 Recently, it was reported that, among working couples, women earn 30 percent less than their husbands do. It's reasonable to conclude that, among working couples, both the median and mean earnings of wives

a) are 30 percent less than that for their husbands.

b) are at least 30 percent less than that for their husbands.

c) are at most 30 percent less than that for their husbands.

d) are less than that for their husbands.

3.24 The mean serves as the single most preferred average for

a) all data.

b) any frequency distribution.

c) quantitative data.

d) ungrouped data.

3.25 Which one of the following is not true of the mean?

a) always best describes the central tendency of a distribution

b) reappears, out of mathematical necessity, throughout statistics

c) serves as a key component in more complex statistical measures

d) emerges as a well‑documented measure to use when generalizing beyond small sets of observations

3.26 If qualitative data can be ordered, it's possible to use

a) any average.

b) the mean or mode.

c) the mean or median.

d) the mode or median.

3.27 Identify the median for the following distribution of

of college students:

CLASS STANDING f

Graduate 250

Senior 300

Junior 350

Sophomore 400

Freshman 700

2000

a) freshman

b) sophomore

c) junior

d) senior

3.28 It would be appropriate to report the median for a distribution of

a) political preferences.

b) countries of birth.

c) academic majors.

d) none of the above

3.29 Ordinarily, average signifies

a) the mode.

b) the median.

c) the mean.

d) the mode, median or mean.

3.30 Which average -- the mode, median, or mean -- probably serves as the basis for the following statement? The average college professor is a white male.

a) mode

b) median

c) mean

d) impossible to determine on the basis of available information

3.31 Which average -- the mode, median, or mean -- probably serves as the basis for the following statement? As of March 2009, the average American's share of the national debt equals approximately $35,000.

a) mode

b) median

c) mean

d) impossible to determine on the basis of available information

3.32 Which average -- the mode, median, or mean -- probably serves as the basis for the following statement? The average wage earner's income is substantially higher than the lowest 50 percent of wage earners.

a) mode

b) median

c) mean

d) impossible to determine on the basis of available information

3.33 Averages are sometimes referred to as measures of central tendency. This description is somewhat misleading particularly when

a) the mean is used with a highly skewed distribution.

b) the median is used with a highly skewed distribution.

c) the mode is used with a highly skewed distribution.

e) none of the above.

3.34 When data are ranked, the most meaningful average is

a) the mode

b) the median

c) the mean

d) all of the above