A watch manufacturer claims that their watches on average will neither gain nor lose time during a week. A sample of 18 watches provided the following gain (+) or losses (-) in seconds per week. -0.61 -0.37 -0.38 -0.32 +0.32 -0.23 -0.20 -0.68 -0.10 -0.20 -0.38 -0.48 -0.47 -0.64 -0.04 +0.30 +0.25 +0.05 (a) What is the point estimate for the true average gain or losses in seconds per week of the watches produced by the manufacturer? (b) Find the 98% confidence interval for the mean gain or loss in time for the watches. (c) Test, at the 0.02 level of significance, whether the mean gain or loss in time for the watches is 0. Is the manufacturer's claim correct? (d) Compute the p-value for the test in (c). (e) State the assumption for the test in (c). (f) Are the results of (b) and (c) consistent?

A stock analyst wondered whether the mean rate of return of financial, energy and utility stocks differed over the past 5 years. He obtained a simple random sample of eight companies from each of the three sectors and obtained the 5-year rates of return shown in the following table (in percents):   Financial Energy Utilities 10.76 12.72 11.88 15.05 13.91   5.86 17.01   6.43 13.46   5.07 11.19   9.90 19.50 18.79   3.95   8.16 20.73   3.44 10.38   9.60   7.11   6.75 17.40 15.70   Source: Morningstar.com   Required:   (a)  State the null and alternative hypothesis. (b)  Are the mean rates of return different at the alpha = 0.05 level of significance? Please explain your answer, citing numeric and other evidence in support of your response.

5.35 Cyberbullying, continued. Refer to Exercise 5.33. a. What is the expected number of undergraduates in your sample who say that they have received hurtful comments online in the past 30 days? What is the expected number of undergraduates who say that they have not received hurtful comments online in the past 30 days? What do the two means add up to?

Twelve percent of the world's population is left-handed. A researcher claims that left-handed individuals are more creative than those who aren't left-handed. In order to support his claim, he takes a sample of 1650 artists and finds that 14% of.them are left-handed. Español Answer the following. (If necessary, consult a list of formulas.) (a) Find the mean of p, where p is the proportion of left-handed individuals in a random sample of 1650. 00 (b) Find the standard deviation of p. (c) Compute an approximation for P (p s0.14), which is the probability that there will be 14% or fewer left-handed people in a random sample of 1650. Round your answer to four decimal places. Save For Later Submit Assignment Check Terms of Use Privacy Center Accessibility acer esc backspa

5t.  A magazine reports that women trust recommendations from a particular social networking site more than recommendations from any other social network platform. But does trust in this social networking site differ by gender? The following sample data show the number of women and men who stated in a recent sample that they trust recommendations made on this particular social networking site.   Women Men Sample 150 170 Trust RecommendationsMade on the social networking site 111 102 (a) What is the point estimate of the proportion of women who trust recommendations made on this particular social networking site?   (b) What is the point estimate of the proportion of men who trust recommendations made on this particular social networking site?   (c) Provide a 95% confidence interval estimate of the difference between the proportion of women and men who trust recommendations made on this particular social networking site. (Round your answers to four decimal places.)

find the z score in which 93.70% of the z scores in a population are below that value