Chapter 10.1, Problem 11P

For Problems 9-17 assume that the distribution of differences d is mound-shaped and symmetric.

Please provide the following information for Problems 9-17.

(a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test?

(b) Check Requirements What sampling distribution will you use? What assumptions are you making ? Compute the value of the sample test statistic and corresponding t value.

(c) Find (or estimate) the P-value. Sketch the sampling distribution and show the area corresponding to the P-value.

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level $\alpha$?

(e) Interpret your conclusion in the context of the application.

In these problems, assume that the distribution of differences is approximately normal.

Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f that is smaller. In some situations, this choice of d.f. may increase the P-value by a small amount and therefore produce a slightly more ‘‘conservative” answer.

Ecology: Rocky Mountain National Park The following is based on information taken from Winter Wind Studies in Rocky Mountain National Park by D. E. Glidden (Rocky Mountain Nature Association). At five weather stations on Trail Ridge Road in Rocky Mountain National Park, the peak wind gusts (in miles per hour) for January and April are recorded below:

Weather Station	1	2	3	4	5
January	139	122	126	64	78
April	104	113	100	88	61

Does this information indicate that the peak wind gusts are higher in January than in April? Use $\alpha =0.01$.