Question 1

The correlation coefficient only measures the direction and strength of a linear relationship between two numerical variables.

Accepted Answer

A) True 
 B)False

Question 2

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

Accepted Answer

Q₃ = 170.25, Q₁ = 150.

Question 3

Chebyshev's theorem relates to only to symmetric histograms.

Accepted Answer

A) True 
 B)False

Question 4

In a bell-shaped distribution, there is no difference in the values of the mean, median and mode.

Accepted Answer

A) True 
 B)False

Question 5

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

Accepted Answer

@#IMG-DLM& There are

Question 6

Compute the coefficient of variation.

Accepted Answer

cv = 0.384

Question 7

A sample of 25 families was asked how many pets they owned. Their responses are summarized in the following table.

$\begin{array}{|l|r|r|r|r|r|r|}
\hline \text { Number of pets } & 0 & 1 & 2 & 3 & 4 & 5 \
\hline \text { Number of families } & 3 & 10 & 5 & 4 & 2 & 1 \
\hline
\end{array}$ a. Determine the mean, the median and the mode of the number of pets owned per family.
b. Describe briefly what each statistic in part (a) tells you about the data.

Accepted Answer

a. x = 1.80 pet, median = 1 pet, mode =

Question 8

Chebyshev's theorem states that the percentage of observations in a data set that should fall within 3 standard deviations of their mean is at least 88.9%.

Accepted Answer

A) True 
 B)False

Question 9

In a negatively skewed distribution, the mean is greater than the median.

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

L²⁵ = 6.5. Q

Question 11

There are no measures of variability for nominal data.

Accepted Answer

A) True 
 B)False

Question 12

Generally speaking, if two variables have a strong positive linear relationship, the covariance between them is equal to one.

Accepted Answer

A) True 
 B)False

Question 13

The following data represent the numbers of bedrooms in a sample of 10 suburban houses in Melbourne: $\begin{array}{|l|l|l|l|l|l|l|l|l|l|}
\hline3 & 3 & 2 & 2 & 4 & 5 & 2 & 5 & 4 & 2 \
\hline
\end{array}$ Use these data to answer the following question/s.
-a. Compute the mean.
b. Compute the median.

Accepted Answer

a. mean =

Question 14

When approximating descriptive measures for grouped data, the sample mean can be obtained by making the assumption that the midpoint of each class closely approximates the mean of each class.

Accepted Answer

A) True 
 B)False

Question 15

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

L₁₅ =10.5. Q₃ = (26.5 +

Question 16

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 variance and standard deviation of the salaries.

Accepted Answer

variance =

Question 17

The coefficient of variation allows us to compare two sets of data based on different measurement units.

Accepted Answer

A) True 
 B)False

Question 18

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 median salary.

Accepted Answer

Median sal

Question 19

Which of the following is the proportion of the total area that must be to the left of the median, in a histogram? $\begin{array}{|l|l|}
\hline  A&\text {0.50 }\
\hline  B&\text { Less than 0.50 if the distribution is skewed to the left.}\
\hline  C&\text { More than 0.50 if the distribution is skewed to the right.}\
\hline  D&\text {Between 0.25 and 0.60 if the distribution is symmetric and unimodal. }\
\hline 
\end{array}$

Accepted Answer

The answer of Which of the following is the proportion...

Question 20

The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2. If the ratios have a mound-shaped distribution, what can we say about the proportion of ratios that fall between:
a. 11.5 and 15.5?
b. 9.5 and 17.5?
c. 7.5 and 19.5?

Accepted Answer

a. The interval contains appro

Exam 5: Numerical Descriptive Measures

The correlation coefficient only measures the direction and strength of a linear relationship between two numerical variables.

The following data represent the weights (in kilograms) of a sample of 30 horses: Weight 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 Are there any outliers?

Chebyshev's theorem relates to only to symmetric histograms.

In a bell-shaped distribution, there is no difference in the values of the mean, median and mode.

The following data represent the ages (in years) of a sample of 25 employees from a government department: 31 43 56 23 49 42 33 61 44 28 48 38 44 35 40 64 52 42 47 39 53 27 36 35 20 Construct a box plot for the age data and identify any outliers.

Compute the coefficient of variation.

Chebyshev's theorem states that the percentage of observations in a data set that should fall within 3 standard deviations of their mean is at least 88.9%.

In a negatively skewed distribution, the mean is greater than the median.

The following data represent the ages (in years) of a sample of 25 employees from a government department: 31 43 56 23 49 42 33 61 44 28 48 38 44 35 40 64 52 42 47 39 53 27 36 35 20 Find the lower quartile of the ages.

There are no measures of variability for nominal data.

Generally speaking, if two variables have a strong positive linear relationship, the covariance between them is equal to one.

The following data represent the numbers of bedrooms in a sample of 10 suburban houses in Melbourne: 3 3 2 2 4 5 2 5 4 2 Use these data to answer the following question/s. -a. Compute the mean. b. Compute the median.

When approximating descriptive measures for grouped data, the sample mean can be obtained by making the assumption that the midpoint of each class closely approximates the mean of each class.

The following data represent the salaries (in thousands of dollars) of a sample of 13 employees of a firm: 26.5 23.5 29.7 24.8 21.1 24.3 20.4 22.7 27.2 23.7 24.1 24.8 28.2 Compute the upper quartile.

The following data represent the salaries (in thousands of dollars) of a sample of 13 employees of a firm: 26.5 23.5 29.7 24.8 21.1 24.3 20.4 22.7 27.2 23.7 24.1 24.8 28.2 Compute the variance and standard deviation of the salaries.

The coefficient of variation allows us to compare two sets of data based on different measurement units.

The following data represent the salaries (in thousands of dollars) of a sample of 13 employees of a firm: 26.5 23.5 29.7 24.8 21.1 24.3 20.4 22.7 27.2 23.7 24.1 24.8 28.2 Compute the median salary.

The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2. If the ratios have a mound-shaped distribution, what can we say about the proportion of ratios that fall between: a. 11.5 and 15.5? b. 9.5 and 17.5? c. 7.5 and 19.5?

What Is Statistics

Types of Data, Data Collection and Sampling

Graphical Descriptive Methods Nominal Data

Graphical Descriptive Techniques Numerical Data

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Statistical Inference: Introduction

Sampling Distributions

Estimation: Describing a Single Population

Estimation: Comparing Two Populations

Hypothesis Testing: Describing a Single Population

Hypothesis Testing: Comparing Two Populations

Inference About Population Variances

Analysis of Variance

Additional Tests for Nominal Data: Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Model Building

Nonparametric Techniques

Statistical Inference: Conclusion

Time-Series Analysis and Forecasting

Index Numbers

Decision Analysis

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