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Expert-verifiedThe health director of a large company is concerned about the effects of stress on the company’s middle-aged male employees. According to the National Center for Health Statistics, the mean systolic blood pressure for males 35 to 44 years of age is 128. The health director examines the medical records of a random sample of 72 male employees in this age group. The Minitab output below displays the results of a significance test and a confidence interval.
1. Do the results of the significance test allow us to conclude that the mean blood pressure for all the company’s middle-aged male employees differs from the national average? Justify your answer.
2. Interpret the 95% confidence interval in context. Explain how the confidence interval leads to the same conclusion as in Question 1.
Part (a) Test is not significant.
Part (b) Null hypothesis is rejected.
The p-value as indicated in the Minitab output is equal to 0.275 which is greater than 0.05. As a result, the test is not significant and there is insufficient evidence to reject the null hypothesis that there is no difference.
The sample mean and test statistic as indicated in the Minitab output is equal to 129.93 and 1.10 respectively. If the sample means is extended to either side of the test statistic at a 95% confidence interval will still belong to the confidence interval. As a result, it shows there is insufficient evidence to reject the null hypothesis that there is no difference.
Eye black Athletes performing in bright sunlight often smear black grease under their eyes to reduce glare. Does cye black work? In one experiment, 16 randomly selected student subjects took a test of sensitivity to contrast after 3 hours facing into bright sun, both with and without eye black. Here are the differences in sensitivity, with eye black mines without eye black:
0.07 | 0.64 | -0.12 | -0.05 | -0.18 | 0.14 | -0.16 | 0.03 |
0.05 | 0.02 | 0.43 | 0.24 | -0.11 | 0.28 | 0.05 | 0.29 |
We want to know whether cye black increases sensitivity an the average.
(a) State hypotheses, Be sure to define the parameter.
(b) Check conditions for carrying out a significance test.
(c) The of the test is . Interpet this value in context.
- Interpret a Type l error and a Type ll error in context, and give the consequences of each.
- Understand the relationsonship between the significance level at a test P(Type li error), and power.
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