Question 1

Which of the following statements best describes the mean of a data set?

Accepted Answer

A) The mean is a measure of spread. 
B) The mean is a measure of central location, defined as the middle value in a sorted set of data. 
C) The mean is a measure of central location, calculated by summing all observations in a data set divided by the number of observations in the data set. 
D) The mean is a measure of central location, defined as the observation in a data set with the highest frequency.

Question 2

The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The female students in the class averaged:

Accepted Answer

A) 75. 
B) 85. 
C) 65. 
D) 70. 
E) 80.

Question 3

When approximating descriptive measures for grouped data, the shape of the distribution within each class is ignored.

Accepted Answer

A) True 
 B)False

Question 4

a. Calculate the covariance and the coefficient of correlation for the following sample. $$\begin{array} { | l | r | r | r | r | r | } 
\hline x & 9 & 6 & 7 & 5 & 8 \
\hline y & 19 & 14 & 16 & 12 & 15 \
\hline
\end{array}$$ b. What do these statistics tell you about the relationship between X and Y?

Accepted Answer

The answer of a. Calculate the covariance and the coefficient...

Question 5

The following data represent the ages (in years) of a sample of 25 employees from a government
department: $$\begin{array} { | l | l | l | l | r | r | r | r | r | r | } 
\hline 31 & 43 & 56 & 23 & 49 & 42 & 33 & 61 & 44 & 28 \
\hline 48 & 38 & 44 & 35 & 40 & 64 & 52 & 42 & 47 & 39 \
\hline 53 & 27 & 36 & 35 & 20 & & & & & \
\hline
\end{array}$$ The frequency distribution for the data, using five class intervals and the value 20 as the lower limit of the first class is given below. $$\begin{array} { c c } 
\hline \text { Class Limits } & \text { Frequency } \
\hline 20 \text { up to } 30 & 4 \
30 \text { up to } 40 & 7 \
40 \text { up to } 50 & 9 \
50 \text { up to } 60 & 3 \
60 \text { up to } 70 & 2 \
\text { Total } & 25 \
\hline
\end{array}$$ Find the mean of the grouped data.

Accepted Answer

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

Question 6

A sample of 16 observations has a standard deviation of 2. Which of the following is the sum of the squared deviations from the sample mean?

Accepted Answer

A) 60. 
B) 64. 
C) 30. 
D) 16.

Question 7

The following data represent the ages (in years) of a sample of 25 employees from a government
department: $$\begin{array} { | l | l | l | l | r | r | r | r | r | r | } 
\hline 31 & 43 & 56 & 23 & 49 & 42 & 33 & 61 & 44 & 28 \
\hline 48 & 38 & 44 & 35 & 40 & 64 & 52 & 42 & 47 & 39 \
\hline 53 & 27 & 36 & 35 & 20 & & & & & \
\hline
\end{array}$$ Calculate the 1st quintile. (Hint: 1st quintile is L20)

Accepted Answer

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

Question 8

Which of the following summary measures is affected by extreme values?

Accepted Answer

A) The median. 
B) The interquartile range. 
C) The range. 
D) The mode.

Question 9

In a positively skewed distribution, the mean is larger than the median and the median is larger than the mode.

Accepted Answer

A) True 
 B)False

Question 10

The following data represent the numbers of bedrooms in a sample of 10 suburban houses in Mel-bourne:
$$\begin{array} { | r | r | r | r | r | r | r | r | r | r | } 
\hline 3 & 3 & 2 & 2 & 4 & 5 & 2 & 5 & 4 & 2 \
\hline
\end{array}$$
Use these data to answer the following question/s.

-a. Compute the mean.
b. Compute the median.

Accepted Answer

The answer of The following data represent the numbers of...

Question 11

A basketball player has the following points for seven games: 20, 25, 32, 18, 19, 22, 30. Compute the following measures of central location and variability:
a. mean.
b. median.
c. standard deviation.
d. coefficient of variation.

Accepted Answer

The answer of A basketball player has the following points...

Question 12

When the distribution is skewed, the interquartile range is a better measure of variability than the standard deviation.

Accepted Answer

A) True 
 B)False

Question 13

Quartiles divide the values in a data set into four parts of equal size.

Accepted Answer

A) True 
 B)False

Question 14

Which measure of variability is appropriate when a sample is likely to contain one or several extreme values?

Accepted Answer

A) The variance. 
B) The standard deviation. 
C) The interquartile range. 
D) The range.

Question 15

The following data provide the hours of television viewing per week for a sample of 15 high school students in Darwin: $$\begin{array} { r | r | r | r | r | r | r | r | } 
5 & 11 & 25 & 19 & 18 & 20 & 27 & 13 \
\hline 8 & 10 & 15 & 19 & 8 & 9 & 12 & \
\hline
\end{array}$$ a. Determine the locations and values of the first, second and third quartiles.
b. Calculate the interquartile range.
c. Interpret the value of the interquartile range.

Accepted Answer

The answer of The following data provide the hours of...

Question 16

The following data are the heights (in cm) of the 25 students in a business statistics class: $$\begin{array} { | l | l | l | l | l | l | l | l | l | l | } 
\hline 164 & 148 & 137 & 157 & 173 & 156 & 177 & 172 & 169 & 165 \
\hline 145 & 168 & 163 & 162 & 174 & 152 & 156 & 168 & 154 & 151 \
\hline 174 & 146 & 134 & 140 & 171 & & & & & \
\hline
\end{array}$$ a. Compute the range of the data.
b. Compute the range approximation to the standard deviation of the data. (Hint: S F1F1F1S1F1F1F10 Range/4.)

Accepted Answer

The answer of The following data are the heights (in...

Question 17

Which of the following statements is true?

Accepted Answer

A) When the distribution is skewed to the left, mean > median > mode. B) When the distribution is skewed to the right, mean < median < mode. C) When the distribution is symmetric and unimodal, mean = median = mode. D) When the distribution is symmetric and bimodal, mean = median = mode.

Question 18

Data from three samples are shown below: $$\begin{array} { | l | r | r | r | r | r | } 
\hline \text { Sample A: } & 17 & 22 & 20 & 18 & 23 \
\hline \text { Sample B: } & 30 & 28 & 35 & 40 & 25 \
\hline \text { Sample C: } & 44 & 39 & 54 & 21 & 52 \
\hline
\end{array}$$ Examine the three samples. Without performing any calculations, indicate which sample has the greatest amount of variability and which sample has the least amount of variability.

Accepted Answer

The answer of Data from three samples are shown below:...

Question 19

If the coefficient of correlation r = +1, then the best-fit linear equation will actually be satisfied by all of the data points.

Accepted Answer

A) True 
 B)False

Question 20

Lily has been keeping track of what she spends on eating out. The last week's expenditures for meals eaten out were $5.69, $5.95, $6.19, $10.91, $7.49, $14.53 and $7.66. The mean amount Lily spends on meals is $8.35.

Accepted Answer

A) True 
 B)False

Exam 5: Numerical Descriptive Measures

Which of the following statements best describes the mean of a data set?

The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The female students in the class averaged:

When approximating descriptive measures for grouped data, the shape of the distribution within each class is ignored.

a. Calculate the covariance and the coefficient of correlation for the following sample. $\begin{array} { | l | r | r | r | r | r | } \hline x & 9 & 6 & 7 & 5 & 8 \\\hline y & 19 & 14 & 16 & 12 & 15 \\\hline\end{array}$ b. What do these statistics tell you about the relationship between X and Y?

A sample of 16 observations has a standard deviation of 2. Which of the following is the sum of the squared deviations from the sample mean?

Which of the following summary measures is affected by extreme values?

In a positively skewed distribution, the mean is larger than the median and the median is larger than the mode.

A basketball player has the following points for seven games: 20, 25, 32, 18, 19, 22, 30. Compute the following measures of central location and variability: a. mean. b. median. c. standard deviation. d. coefficient of variation.

When the distribution is skewed, the interquartile range is a better measure of variability than the standard deviation.

Quartiles divide the values in a data set into four parts of equal size.

Which measure of variability is appropriate when a sample is likely to contain one or several extreme values?

Which of the following statements is true?

If the coefficient of correlation r = +1, then the best-fit linear equation will actually be satisfied by all of the data points.

Lily has been keeping track of what she spends on eating out. The last week's expenditures for meals eaten out were $5.69, $5.95, $6.19, $10.91, $7.49, $14.53 and $7.66. The mean amount Lily spends on meals is $8.35.