Exam 4: Numerical Descriptive Techniques

The y-intercept of the least squares line is the point on the line when ________________ = 0.

Ages of Workers The ages (in years) of three groups of workers are shown below: -{Ages of Workers Narrative} Compute and compare the ranges for the three groups.

The data set 10, 20, 30 has the same variance as the data set 100, 200, 300.

The Empirical Rule states that the percentage of observations in a data set (providing that the data set is bell shaped) that fall within one standard deviation of their mean is approximately 75%.

Chebysheff's Theorem states that the percentage of measurements in a data set that fall within three standard deviations of their mean is:

Ages of Jockeys The following data represent the ages in years of a sample of 25 jockeys from a local race track: 31, 43, 56, 23, 49, 42, 33, 61, 44, 28, 48, 38, 44, 35, 40, 64, 52, 42, 47, 39, 53, 27, 36, 35, and 20. -{Ages of Jockeys Narrative} a. Construct a relative frequency histogram for the data. b. What does the histogram tell you about the distribution of the data?

Hours Worked per Week The following data represent the hours worked per week 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, and 20. -{Hours Worked per Week Narrative} Find the median hours.

A scatter diagram reveals a strong positive linear relationship between oil and gasoline prices.Which of the following numerical techniques will not give us more detailed information about this relationship?

Weights of Police Officers The following data represent the weights in pounds of a sample of 25 police officers: 164, 148, 137, 157, 173, 156, 177, 172, 169, 165, 145, 168, 163, 162, 174, 152, 156, 168, 154, 151, 174, 146, 134, 140, and 171. -{Weights of Police Officers Narrative} Determine the location and value of the upper quartile of the weights.

There are three measures of central location; the mean, the ____________________, and the ____________________.

Scatter diagrams, covariance, and the coefficient of correlation are useful techniques for detecting relationships between two ____________________ variables.

In a histogram, the proportion of the total area which must be to the right of the mean is exactly 0.50 if the distribution is symmetric and unimodal.

The line drawn within the box of a box plot always represents the median.

Which of the following are measures of the linear relationship between two variables?

Box plots and medians work well to describe ____________________ data, while histograms and means work well to describe ____________________ data.

Chebysheff's Theorem states that the percentage of observations in a data set that should fall within five standard deviations of their mean is at least 96%.

Suppose a sample of size 50 has a sample mean of 20.In this case, the sum of all observations in the sample is 1,000.

A box plot is a graphical representation of the 5-number summary.

2-Year Investment Suppose you make a 2-year investment of $5,000 and it grows by 100% to $10,000 during the first year.During the second year, however, the investment suffers a 50% loss, from $10,000 back to $5,000. -{2-Year Investment Narrative} Calculate the arithmetic mean.

If the coefficient of correlation r = 1, then the best-fit linear equation will actually include all of the observations.