Exam 4: Numerical Descriptive Techniques

The Y-intercept, b₀, of the least squares line represents the:

The sample mean is denoted by ____________________ and the population mean is denoted by ____________________.

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

Weights of Workers The following data represent the number of employees of a sample of 25 companies: 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 Workers Narrative} Find the mean number of workers.

The mean is affected by extreme values but the median is not.

If the covariance of x and y is 26.16 and the standard deviation of x is 32.7, then the slope of the least squares line is b₁ =.80.

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

If the first and second quartiles are farther apart than the second and third quartiles, then the shape of the histogram based on the quartiles is ____________________.

The mean is a measure of variability.

The strength of the linear relationship between two interval variables can be measured by the:

If , , n = 12, and the slope equals 0.5, then the y-intercept of the least squares line is b₀ = 276.08.

Lily has been keeping track of what she spends to eat out.The last week's expenditures for meals eaten out were $5.69, $5.95, $6.19, $10.91, $7.49, $14.53, and $7.66.The mean amount Lily spends on meals is $8.35.

Pets Survey A sample of 36 families were asked how many pets they owned.Their responses are summarized in the following table. -{Pets Survey Narrative} Explain what the mean, median, and mode tell you about this particular data set.

Weights of Workers The following data represent the number of employees of a sample of 25 companies: 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 Workers Narrative} Is the distribution of the number of workers symmetric or skewed? Why?

Which of the following statements about the median is not true?

Weights of Workers The following data represent the number of employees of a sample of 25 companies: 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. -The number of hours a college student spent studying during the final exam week was recorded as follows: 7,6, 4, 9, 8, 5, and 10.Compute for the data and the value in an appropriate unit.

Strip Mall Rent Monthly rent data in dollars for a sample of 10 stores in a small town in South Dakota are as follows: 220, 216, 220, 205, 210, 240, 195, 235, 204, and 250. -{Strip Mall Rent Narrative} Compute the sample median.

Is it possible for the standard deviation of a data set to be larger than its variance? Explain.

Milk Demand A supermarket has determined that daily demand for milk containers has an approximate bell shaped distribution, with a mean of 55 containers and a standard deviation of six containers. -{Milk Demand Narrative} What percentage of the time will the number of containers of milk sold be more than 2 standard deviations from the mean?

If the coefficient of correlation r = -.81, the standard deviations of x and y are 20 and 25, respectively, then cov(x, y) must be -405.0.