Exam 5: Numerical Descriptive Measures

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 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 90th percentile.

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 Compute the interquartile range of the 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 Determine the location and value of the 65th percentile of the weights.

The standard deviation is expressed in terms of the original units of measurement, but the variance is not.

According to the empirical rule, which of the following is the approximate percentage of measurements in a data set (provided that the data set has a bell-shaped distribution) that fall within two standard deviations of their mean?

The left side of the box in a boxplot is the first quartile and the right side of the box in a boxplot is the third quartile, so the width of the box is the interquartile range.

While Chebyshev's theorem applies to any distribution, regardless of shape, the empirical rule applies only to distributions that are bell-shaped and symmetrical.

If the coefficient of correlation r = 0, then there is no linear relationship between the dependent variable y and the independent variable x.