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.

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 Find the median weight.

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.

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 median age.

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 60th percentile of the ages.

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.

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.

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 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.

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 variance and sample standard deviation.

Chebyshev's theorem relates to only to symmetric histograms.