Author:
Christine Farr

A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the 0.10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?Pine trees Spruce treesSample size 25 35Mean trunk diameter (cm) 55 48Sample variance 100 140What is the test value for this hypothesis test?Test value: Round your answer to three decimal places.What is the critical value?Critical value: Round your answer to three decimal places.Part 4 of 8 -Question 10 of 17 1.0 PointsThe marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results:Store Shelf Space(X) Weekly Sales(Y)1 10 2.02 10 2.63 10 1.84 15 2.35 15 2.86 15 3.07 20 2.78 20 3.19 20 3.210 25 3.011 25 3.312 25 3.5Find the equation of the regression line for these data. What is the value of the coefficient of determination? Place your answer, rounded to 3 decimal places, in the blank. Do not use a dollar sign. For example, 0.345 would be a legitimate entry. Question 11 of 17 1.0 Points The marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results:Store Shelf Space(X) Weekly Sales(Y)1 10 2.02 10 2.63 10 1.84 15 2.35 15 2.86 15 3.07 20 2.78 20 3.19 20 3.210 25 3.011 25 3.312 25 3.5Using the equation of the regression line for these data, predict the average weekly sales (in hundreds of dollars) of international food for stores with 13 feet of shelf space for international food.Place your answer, rounded to 3 decimal places , in the blank. Do not use a dollar sign. For example, 2.345 would be a legitimate entry. Part 5 of 8 -Question 12 of 17 1.0 PointsQ-Mart is interested in comparing its male and female customers. Q-Mart would like to know if the amount of money spent by its female charge customers differs, on average, from the amount spent by its male charge customers. To answer this question, an analyst collected random samples of 25 female customers and 22 male customers. Based on these samples, on average, the 25 women charge customers spent $102.23 and the 22 men charge customers spent $86.46. Moreover, the sample standard deviation of the amount charged by the 25 women was $93.393, and the sample standard deviation of the amount charged by the 22 men was $59.695. Suppose, using a 10% level of significance, you wish to know if there is sufficient evidence for Q-Mart to conclude that, on average, the amount spent by women charge customers differs from the amount spent by men charge customers. That is suppose you wish to test H0: versus H1

Tutorial