Question 1

The value of the standard deviation may be either positive or negative, while the value of the variance will always be positive.

Accepted Answer

A) True 
 B)False

Question 2

The following data represent the weights (in kilograms) of a sample of 30 horses: Weight
$$\begin{array} { l } 
165 \
175 \
150 \
155 \
173 \
149 \
145 \
153 \
153 \
153 \
152 \
145 \
164 \
143 \
170 \
175 \
148 \
174 \
171 \
156 \
166 \
168 \
152 \
150 \
173 \
168 \
146 \
155 \
172 \
159
\end{array}$$ Find the median weight.

Accepted Answer

The answer of The following data represent the weights (in...

Question 3

Which of the following statements is true?

Accepted Answer

A) When approximating the sample mean for grouped data we assume that the mid-point of each class closely approximates the mean of observations in the class. 
B) When approximating the sample mean for grouped data we cannot assume that the midpoint of each class closely approximates the mean of observations in the class. 
C) Descriptive measures for grouped data are not possible. 
D) None of these choices are correct.

Question 4

A courier company is reviewing their delivery times. The following descriptive statistics relates to this courier company. The mean time for package delivery is 5 hours, the first quartile is 4 hours, the third quartile is 17 hours. This means that the 25% of the deliveries take more than 17 hours.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following statements is true?

Accepted Answer

A) The standard deviation is always greater than the variance. 
B) The sum of the squared deviations from the mean is always zero. 
C) The standard deviation is in squared units. 
D) The sum of the deviations from each value in a data set to the mean, is always zero.

Question 6

Using percentiles, the difference between which of the following is the interquartile range?

Accepted Answer

A) 10% and 90% values. 
B) 25% and 75% values. 
C) 15% and 85% values. 
D) 30% and 70% values.

Question 7

The coefficient of determination may range in values between negative one and positive one.

Accepted Answer

A) True 
 B)False

Question 8

The following data represent the ages (in years) of a sample of 25 employees from a government
department: $$\begin{array} { | l | l | l | l | r | r | r | r | r | r | } 
\hline 31 & 43 & 56 & 23 & 49 & 42 & 33 & 61 & 44 & 28 \
\hline 48 & 38 & 44 & 35 & 40 & 64 & 52 & 42 & 47 & 39 \
\hline 53 & 27 & 36 & 35 & 20 & & & & & \
\hline
\end{array}$$ Find the median age.

Accepted Answer

The answer of The following data represent the ages (in...

Question 9

The following data represent the ages (in years) of a sample of 25 employees from a government
department: $$\begin{array} { | l | l | l | l | r | r | r | r | r | r | } 
\hline 31 & 43 & 56 & 23 & 49 & 42 & 33 & 61 & 44 & 28 \
\hline 48 & 38 & 44 & 35 & 40 & 64 & 52 & 42 & 47 & 39 \
\hline 53 & 27 & 36 & 35 & 20 & & & & & \
\hline
\end{array}$$ Find the 60th percentile of the ages.

Accepted Answer

The answer of The following data represent the ages (in...

Question 10

A linear regression model estimating the relationship between Expenditure on Imports and Annual household income has a coefficient of correlation r of 0.90.
Interpret r.

Accepted Answer

The answer of A linear regression model estimating the relationship...

Question 11

The following data represent the salaries (in thousands of dollars) of a sample of 13 employees of a firm: $$\begin{array} { | l | l | l | l | l | l | l | } 
\hline 26.5 & 23.5 & 29.7 & 24.8 & 21.1 & 24.3 & 20.4 \
\hline 22.7 & 27.2 & 23.7 & 24.1 & 24.8 & 28.2 & \
\hline
\end{array}$$ Compute the upper quartile.

Accepted Answer

The answer of The following data represent the salaries (in...

Question 12

Data were obtained for the weight in grams, of a sample of 10 packets of sweetener, as found in cafés. $$\begin{array} { | l | l | l | l | l | l | l | l | l | l | } 
\hline 4.5 & 5 & 5.9 & 5.4 & 5.5 & 4.7 & 4.9 & 4.7 & 4.7 & 4.6 \
\hline
\end{array}$$ Find the range

Accepted Answer

The answer of Data were obtained for the weight in...

Question 13

The coefficient of correlation is always the same value as the coefficient of determination.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following statements describes when the median is a better measure of centre than the mean?

Accepted Answer

A) When the distribution is symmetric. 
B) When the distribution is positively skewed. 
C) When the distribution Is negatively skewed. 
D) When the distribution is positively skewed or negatively skewed.

Question 15

What measure of central location is best used with a categorical variable?

Accepted Answer

A) The mean, median or the mode if the distribution is symmetric. 
B) The median if the distribution is skewed. 
C) The range. 
D) The mode.

Question 16

A linear regression model estimating the relationship between Expenditure on exports ($) and Annual household income ($) is as follows:
Estimated Expenditure on Exports = 3.55 − 0.02Annual household income
Interpret the slope.

Accepted Answer

The answer of A linear regression model estimating the relationship...

Question 17

Which of the following statements is true for the following data values: 7, 5, 6, 4, 7, 8 and 12?

Accepted Answer

A) The mean, median and mode are all equal. 
B) Only the mean and median are equal. 
C) Only the mean and mode are equal. 
D) Only the median and mode are equal.

Question 18

The least squares method is the method of deriving a linear equation between two numerical variables.

Accepted Answer

A) True 
 B)False

Question 19

The following data represent the weights (in kilograms) of a sample of 30 horses: Weight
$$\begin{array} { l } 
165 \
175 \
150 \
155 \
173 \
149 \
145 \
153 \
153 \
153 \
152 \
145 \
164 \
143 \
170 \
175 \
148 \
174 \
171 \
156 \
166 \
168 \
152 \
150 \
173 \
168 \
146 \
155 \
172 \
159
\end{array}$$ Compute the sample variance and sample standard deviation.

Accepted Answer

The answer of The following data represent the weights (in...

Question 20

Chebyshev's theorem relates to only to symmetric histograms.

Accepted Answer

A) True 
 B)False

Exam 5: Numerical Descriptive Measures

The value of the standard deviation may be either positive or negative, while the value of the variance will always be positive.

Which of the following statements is true?

A courier company is reviewing their delivery times. The following descriptive statistics relates to this courier company. The mean time for package delivery is 5 hours, the first quartile is 4 hours, the third quartile is 17 hours. This means that the 25% of the deliveries take more than 17 hours.

Which of the following statements is true?

Using percentiles, the difference between which of the following is the interquartile range?

The coefficient of determination may range in values between negative one and positive one.

A linear regression model estimating the relationship between Expenditure on Imports and Annual household income has a coefficient of correlation r of 0.90. Interpret r.

Data were obtained for the weight in grams, of a sample of 10 packets of sweetener, as found in cafés. $\begin{array} { | l | l | l | l | l | l | l | l | l | l | } \hline 4.5 & 5 & 5.9 & 5.4 & 5.5 & 4.7 & 4.9 & 4.7 & 4.7 & 4.6 \\\hline\end{array}$ Find the range

The coefficient of correlation is always the same value as the coefficient of determination.

Which of the following statements describes when the median is a better measure of centre than the mean?

What measure of central location is best used with a categorical variable?

A linear regression model estimating the relationship between Expenditure on exports ($) and Annual household income ($) is as follows: Estimated Expenditure on Exports = 3.55 − 0.02Annual household income Interpret the slope.

Which of the following statements is true for the following data values: 7, 5, 6, 4, 7, 8 and 12?

The least squares method is the method of deriving a linear equation between two numerical variables.

Chebyshev's theorem relates to only to symmetric histograms.