Exam 5: Numerical Descriptive Measures

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

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 range.

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 Compute the sample mean weight.

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

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.

A sample of eight observations of variables x and y is shown below: x 5 3 7 9 2 4 6 8 y 20 23 15 11 27 21 17 14 Draw the scatter diagram and plot the least-squares line.

In a symmetric distribution, the mean is the most used measure of central location for quantitative data.

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 Construct a box plot for the weights.

The following data are the heights (in cm) of the 25 students in a business statistics class: 164 148 137 157 173 156 177 172 169 165 145 168 163 162 174 152 156 168 154 151 174 146 134 140 171 a. Compute the sample mean height. b. Compute the sample variance. c. Compute the sample standard deviation.

Which of the following may be answered by knowing the shape of the distribution?

The frequency histogram for the heights (in cm) of the 25 students in a business statistics class is given below. What is the best measure of central location?

When a distribution is symmetric, the mean, median and the mode are all equal.

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 Compute the range and interquartile range of the data.

Data were obtained for the weight in grams, of a sample of 10 packets of sweetener, as found in cafés. 4.5 5 5.9 5.4 5.5 4.7 4.9 4.7 4.7 4.6 Find the variance.

Chebyshev's theorem applies only to data sets that have a mound-shaped distribution.

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 coefficient of variation.

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.

A media article claimed that there was a correlation between the colour of a car and the likelihood of a car being in an accident. What is wrong with this statement?

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

How is the value of the correlation coefficient r affected in each of the following cases? a. Each x value is multiplied by 4. b. Each x value is switched with the corresponding y value. c. Each x value is increased by 2.