Question 1

Below is a summary of data about violent crime rates (number of violent crimes per 100,000 population) for a sample of 20 cities in two different years. Describe this statistical information in words. What changes occurred in the overall shape of the distribution for this variable? In central tendency? In dispersion?

Accepted Answer

The answer of Below is a summary of data about...

Question 2

Table 3.2 Park Space in Five Neighbourhoods of a Fictional City
 
-Refer to Table 3.2. What would be the most appropriate measure of central tendency for the distribution of park space?

Accepted Answer

A)  the mode 
B)  the median 
C)  the mean 
D)  the interquartile range

Question 3

Which of the following is the lowest valid score for a standard deviation?

Accepted Answer

A)  -3 
B)  -1 
C)  0 
D)  0.5

Question 4

Environmental violations for 16 companies ranged from values of 11 to 97. The variance was 14. How should we calculate the standard deviation for this distribution?

Accepted Answer

A)  = 4  
B)  (97 - 11) × 14 = 1204 
C)  142 = 196 
D)  = 3.74

Question 5

Suppose you rank-ordered a set of 49 scores. What would be the median?

Accepted Answer

A)  the 25th case 
B)  the average of the 24th and 25th cases 
C)  the average of cases 1-24 added to the average of cases 25-49 
D)  the summation of each score divided by 49

Question 6

A small-scale coffee producer sent out the following number of bags of coffee beans each week over the course of last June: 6, 8, 10, 17. What is the median weekly value for that month?

Accepted Answer

A)  6.5 
B)  8 
C)  9 
D)  10

Question 7

A researcher reports that $18,000 represents the first quartile of Canadians' incomes. Which of the following is another term he could use to describe that dollar value?

Accepted Answer

A)  median 
B)  first percentile 
C)  second percentile 
D)  25th percentile

Question 8

Suppose we have yearly unemployment data for OECD countries. Which measure of central tendency would be the most appropriate for this data set?

Accepted Answer

A)  index of qualitative variation 
B)  dispersion ratio 
C)  mode 
D)  mean

Question 9

A researcher asked 12 people in an apartment building what was their social class: upper-, middle-, or lower-class. What would be an appropriate measure of central tendency for this distribution?

Accepted Answer

A)  range 
B)  mean 
C)  median 
D)  index of qualitative variation

Question 10

What would be an appropriate measure of dispersion for a set of values of people's ages, measured in years?

Accepted Answer

A)  the mean 
B)  the mode 
C)  the standard quartile 
D)  the standard deviation

Question 11

Which index of qualitative variation scores shows the least amount of variation in a distribution?

Accepted Answer

A)  0.08 
B)  0.22 
C)  0.50 
D)  1.00

Question 12

Which of the following is among the problems with using the range (R) as a measure of dispersion?

Accepted Answer

A)  R can be used only for nominal-level variables. 
B)  R is very difficult to calculate. 
C)  R ignores the most extreme scores. 
D)  R is based on only the most extreme scores.

Question 13

How does the standard deviation formula differ for samples and populations?

Accepted Answer

A)  Xi is used to represent the score of a variable in the population; N is used to represent scores in a sample. 
B)  Xi is used to represent the score of a variable in the sample; N is used to represent scores in a population. 
C)  ì is used to represent the population mean;  is used to represent a sample's mean. 
D)  Standard deviations can be calculated for samples only, not for populations.

Question 14

Table 3.1 Data Set of Six Volunteers at a Charitable Organization
 
-Refer to Table 3.1. What is the median of years served in the organization?

Accepted Answer

A)  2 
B)  2.5 
C)  3 
D)  5

Question 15

The mayor of a city (City A) was wondering whether her city has shown that more new companies start up in City A than in another city of similar size. She asked her staff to gather the number of new companies started annually in her city from 2006 to 2017. She obtained similar data from her comparison city (City B). Compute the mode, mean, median, range, and standard deviation for both cities.

Accepted Answer

The answer of The mayor of a city (City A)...

Question 16

Suppose low variability in a runner's heart rate during a long distance run is a good indication of cardiopulmonary fitness. Which of these statistics measuring pulse rates during a 20 km run would be best?

Accepted Answer

A)  standard deviation = 0.25 beats per minute 
B)  standard deviation = 0.75 beats per minute 
C)  standard deviation = 1.6 beats per minute 
D)  standard deviation = 2.2 beats per minute

Question 17

When would it be especially appropriate to rely on the interquartile range rather than the range to describe a sample's distribution?

Accepted Answer

A)  when the distribution is symmetrical with no outlying values in the distribution 
B)  when the distribution is slightly negatively skewed with no outlying values in the distribution 
C)  when the distribution's mean, median, and mode are nearly equal 
D)  when there are outlying values in the distribution

Question 18

What is the term for a distribution that has its peak on the left and a tail extending far to the right?

Accepted Answer

A)  positively skewed 
B)  negatively skewed 
C)  normally distributed 
D)  bimodally distributed

Question 19

The distribution of film genre preferences in a retirement community of 150 seniors is as follows: Drama-37%; Comedy-32%; Musicals-8%; Action-18%; Documentaries-5%. Why is it impossible to calculate a standard deviation for this variable?

Accepted Answer

A)  The variable's categories are not mutually exclusive. 
B)  The variable's categories do not sum to 100%. 
C)  The variable is too skewed to calculate the variance. 
D)  The variable does not have a mean value.

Question 20

Table 3.1 Data Set of Six Volunteers at a Charitable Organization
 
-Refer to Table 3.1. What is the median of employment status?

Accepted Answer

A)  full-time worker 
B)  student 
C)  part-time worker 
D)  There is no valid median score.

Exam 3: Measures of Central Tendency and Dispersion

Table 3.2 Park Space in Five Neighbourhoods of a Fictional City -Refer to Table 3.2. What would be the most appropriate measure of central tendency for the distribution of park space?