CHAPTER 10a EXERCISES 1. Suppose we perform a valid 1-sided F-test on the populations of male and fe
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CHAPTER 10a EXERCISES1. Suppose we perform a valid1-sided F-test on the populations of male and female Angus beef cattle. The sample of males has a higher standarddeviation. We correctly compute thep-value to be 0.068. If we are doingthis F-test at α = 0.05, what is our conclusion?2. A bolt manufacturer is usinga hypothesis test with α = 0.01 to see if the diameter oftheir 0.75 cm diameter bolts are being manufactured properly. The goal is to have the average bolt diameterbe 0.75 ± 0.0075 cms. (Thus, a 2-sided test with difference of 0.0075 is used.)They know that the standard deviation of the 0.75 cm bolts is 0.028 cms. Use Minitab to compute the sample sizenecessary to achieve a power of 0.9.According to the Power Curve, ifadifference of 0.0025 must be used, what is the approximate power of the testusing this sample size? Copy and pasteor attach your Minitab output to your paper.3. In a contentious shareholderlawsuit, a critical claim by the plaintiffs is that average CEO tenure for companiesof at least $2 billion in market cap is 9 years. A survey of 36 such companies had a samplemean of 7.90 with a sample standard deviation of 6.45. Use this sample to test at the 5% levelwhether the average CEO tenure is less than 9 years. Do the test by hand (using Minitab just forthe p-value) and confirm your results with Minitab. Interpret your results and state yourconclusion in terms of the data.4. Statistical significance, Power, and Practicalsignificance – A Big Data Issue: As amarketing associate for a sports apparel company, we see that, in 2011, 44.2%of our customers checked reviews of our new products on social media sitesbefore buying. This year, to see if thatpercentage has increased, we use an email campaign to survey our recentcustomers. Of 39,994 respondents, 17,885said that, before buying, they checked reviews of the product they purchased onsocial media.a. Based on this survey, what isthe point estimate of the proportion of our customers who check social mediareviews?b. Test whether the increaseindicated by this point estimate is statistically significant?c. Compute a 95% confidenceinterval for the percentage of customers using social media before buying. What do we think about it?d. What is the power of the testin part b?e. Based on this analysis, wouldyou recommend any changes in our social media marketing approach? “Looking for a Similar Assignment? Get Expert Help at an Amazing Discount!” “Is this question part of your assignment? We Can Help!”
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