# Statistics Review - Significance Level, P-Value

1. A financial analyst wants to compare the turnover rates, in percent, for shares of oil-related stocks versus other stocks, such as GE and IBM. She selected 32 oil-related stocks and 49 other stocks. The mean turnover rate of oil-related stocks is 31.4 percent and the standard deviation 5.1 percent. For the other stocks, the mean rate was computed to be 34.9 percent and the standard deviation 6.7 percent. Is there a significant difference in the turnover rates of the two types of stock? Use the .01 significance level.

2. The Tampa Bay (Florida) Area Chamber of Commerce wanted to know whether the mean weekly salary of nurses was larger than that of school teachers. To investigate, they collected the following information on the amounts earned last week by a sample of school teachers and nurses: (see attached) Is it reasonable to conclude that the mean weekly salary of nurses is higher? Use the .01 significance level. What is the p-value?

3. A nationwide sample of influential Republicans and Democrats was asked as a part of a comprehensive survey whether they favored lowering environmental standards so that high-sulfur coal could be burned in coal-fired power plants. The results were: (see attached) At the .02 level of significance, can we conclude that there is a larger proportion of Democrats in favor of lowering the standards?

4. The Engineering Department at Sims Software, Inc., recently developed two chemical solutions designed to increase the usable life of computer disks. A sample of disks treated with the first solution lasted 86, 78, 66, 83, 84, 81, 84, 109, 65, and 102 hours. Those treated with the second solution lasted 91, 71, 75, 76, 87, 79, 73, 76, 79, 78, 87, 90, 76, and 72 hours. At the .10 significance level, can we conclude that there is a difference in the length of time the two types of treatment

lasted?

https://brainmass.com/statistics/hypothesis-testing/statistics-review-significance-level-p-value-43949

#### Solution Preview

1.

Oil Stocks Other Stocks

Average 31.40 34.90

Standard Deviation 5.10 6.70

Number of observations 32 49

Hypothesis to be tested

H0 ...

#### Solution Summary

The solution provides a step-by-step explanation, expressed through excel, on how to determine if there is a significant difference in turnover rates and determining the p-level.