Question

After reviewing data from a sample, an inference can be made about the population. Find a data set on the internet. Some suggested search terms: Free Data Sets, Medical Data Sets, Education Data Sets.

A. Introduce your Data Set and Cite the Source.

B. What trends do you notice in your data set?

C. Based on the trends and the history of your data set, make a claim. What kind of test (left, right, two tailed) would you have to complete?

D. Explain the steps needed to complete the Hypothesis Test. What is needed?

Answer 1

NASA has been working with utility companies to set up expensive power generating windmills. In order for a site to be effective, the average wind speed must be more than 20 mph. At a specific site, NASA took a sample of forty-five wind speed readings. The sample average wind speed is 21.7 mph with a standard deviation of 4.2 mph. NASA will only build the windmill if they are sure that the true average wind speed is greater than 20 mph. Should they build the windmill? Justify by conducting a hypothesis test at α = 0.05.

The hypothesis being tested is:

H0: µ = 20

Ha: µ > 20

The test statistic, t = (x - µ)/s/√n

t = (21.7 - 20)/4.2/√45 = 2.715

The p-value is 0.0047.

Since the p-value (0.0047) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that the true average wind speed is greater than 20 mph.

Thus, they should not build the windmill.