The body lengths of deer mice are known to vary approximately normally, with mean 86 mm and standard deviation 8 mm. A research group is interested whether vitamin supplements will increase deer mouse body length. They select a random sample of 100 deer mice from the population of all deer mice that would ever receive vitamin supplements and observe their body lengths. Suppose the sample mean is calculated as 87.2 mm. Let u be the mean body length of deer mice who receive vitamin supplements. Provide the null and alternative hypotheses most appropriate for this situation. A. Ho: H = 86 vs. Ha: µ> 86 B. Họ: H = 87.2 vs. Ha: µ< 87.2 O C. Ho: u= 86 vs. Ha: H< 86 D. Ho: u = 87.2 vs. Ha: H +87.2 E. Ho: u =87.2 vs. Ha: u> 87.2 Reset Selection

In a randoms sample of six people, the mean driving distance to work was 19.7 miles and the standard deviation was 6.1 miles. Assume the population is normally distributed and use the t-distribution to find the margin of error and construct a 90% confidence interval for the population mean u. Interpret the results.

Find the 95% confidence interval for the variance and standard deviation for the time it takes a state police inspector to check a truck for safety if a sample of 21 trucks has a standard deviation of 5.2 minutes. Assume the variable is normally distributed.

The average gold content from an ore sample in 36 different locations is found to be 2.6 grams per ton. a. Find the 95% and 99% confidence intervals for the mean gold content in that area. Assume that the population variance is 0.09.

Bone mineral density (BMD) is a measure of bone strength. Studies show that BMD declines after age 45. The impact of exercise may increase BMD. A random sample of 59 women between the ages of 41 and 45 with no major health problems were studied. The women were classified into one of two groups based upon their level of exercise activity: walking women and sedentary women. The 39 women who walked regularly had a mean BMD of 5.96 with a standard deviation of 1.22. The 20 women who are sedentary had a mean BMD of 4.41 with a standard deviation of 1.02. Which of the following inference procedures could be used to estimate the difference in the mean BMD for these two types of women

A sports writer wants to see if a football filled with helium travels farther, on average, than a football filled with air. 12 footballs were filled with helium to the recommend pressure and 15 footballs were filled with air to the recommended pressure. The mean yardage for the helium filled footballs was 267 yards with a standard deviation of 3 yards. The mean yardage for the air filled footballs was 241 yards with a standard deviation of 5 yards. Assume the populations are normal with equal variances. (a). Construct a 99% confidence interval for the mean difference in in yardage for the two types of footballs Lower bound (use 3 decimal places) Upper bound (use 3 decimal places) (b). What can you conclude about the sports writer's idea that helium footballs travel farther, on average? The helium footballs are no different than the other footballs, on average The other footballs travel farther on average than the helium footballs The helium footballs travel farther on average than the…

Two estimates are available for the same population parameter. Estimate one has a standard deviation of 8.5 and estimate two has a standard deviation of 8.7. Estimate two is unbiased, whereas estimate one is biased. Which estimate would you choose and why?

The​ quality-control manager at a compact fluorescent light bulb​ (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7,508 hours. The population standard deviation is 840 hours. A random sample of 49 light bulbs indicates a sample mean life of 7,328 hours. Let μ be the population mean. Determine the null​ hypothesis, H0​, and the alternative​ hypothesis, H1.

A non-symmetric dataset has a mean of 200 and a standard deviation of 15.  Find an upper bound for the proportion of data points that are either greater than 230 or less than 170.

If the sample mean is 8, the hypothesized population mean is 4, and the population standard deviation is 2, compute the test value needed for the z test.