An auto insurance company suspect that recently the average cost of vehicle repairs per accident has increased from the average past cost of $3,800. A sample of 20 accident cases yielded sample mean cost of $4,065 and st. dev of $214. Test the hypothesis to confirm the suspicion at  Assume that the repairing cost follows normal distribution. (a) Solve the problem using classical approach. You must state the null and the alternative hypotheses. (b) Solve the problem using p-value approach.

Big fish: A sample of 250 flounder of a certain species have sample mean weight 50.5 grams. Scientists want to perform a hypothesis test to determine how strong the evidence is that the mean weight is less than 49 grams. State the appropriate null and alternate hypotheses.

Gestation period is the length of pregnancy, or to be more precise, the interval between fertilization and birth. In Syrian hamsters, the average gestation period is 16 days. Suppose you have a sample of 31 Syrian hamsters who were exposed to high levels of the hormone progesterone when they were pups, and who have an average gestation length of 17.1 days and a sample variance of 26.0 days. You want to test the hypothesis that Syrian hamsters who were exposed to high levels of the hormone progesterone when they were pups have a different gestation length than all Syrian hamsters.   Calculate the t statistic. To do this, you first need to calculate the estimated standard error. The estimated standard error is sMM= a. 31, b. 0.5232, c. 0.7328, d. 0.9158.    The t statistic is- a. 1.50, b. 2.10, c. 2.63, d. 1.20     Now suppose you have a larger sample size n = 95. Calculate the estimated standard error and the t statistic for this sample with the same sample average and the same…

(b) Is there sufficient evidence to conclude, at the 5% level of significance, that the false positive rate is less than 5%? Explain.

Suppose you want to test the claim that a population mean equals 40. (a) State the null hypothesis. H0: μ > 40 H0: μ < 40     H0: μ = 40 H0: μ ≠ 40 H0: μ ≥ 40 (b) State the alternate hypothesis if you have no information regarding how the population mean might differ from 40. H1: μ > 40 H1: μ < 40     H1: μ = 40 H1: μ ≠ 40 H1: μ ≥ 40 (c) State the alternative hypothesis if you believe (based on experience or past studies) that the population mean may exceed 40. H1: μ > 40 H1: μ < 40     H1: μ = 40 H1: μ ≠ 40 H1: μ ≥ 40

Which best illustrates the distinction between statistical significance and practical importance?     Multiple Choice   "This year, 360 of 440 statistics students at Oxnard Technical College rented their textbooks, compared with 110 of 330 students last year. This is a significant increase."     "Our new manufacturing technique has increased the life of the 80 GB USB AsimoDrive external hard disk significantly, from 240,000 hours to 250,000 hours."     "In 50,000 births, the new vaccine reduced the incidence of infant mortality in Morrovia significantly from 14.2 deaths per 1000 births to 10.3 deaths per 1000 births."     "The new Sky Penetrator IV business jet’s cruising range has increased significantly from 3,975 miles to 4,000 miles."

Tourism is extremely important to the economy of Florida. Hotel occupancy is an often-reported measure of visitor volume and visitor activity (Orlando Sentinel). Hotel occupancy data for February in two consecutive years are as follows Current Year Previous Year Осcupied Rooms 1,470 1,458 Total 1,750 1,800 Rooms (a) Formulate the hypothesis test that can be used to determine if there has been an increase in the proportion of rooms occupied over the one-year period. (Let p, population proportion of rooms occupied for current year and P2 = population proportion of rooms occupied for previous year.) Ho: P1-P22 0 H: P1- P2 0 Ho: P1- P2 0 Hai P1 P2 = 0 Ho: P1- P2 = 0 H P1- P2 0 Ho: P1- P2 # 0 Hi P1- P2 = 0 (b) What is the estimated proportion of hotel rooms occupied each year? current previous (c) Calculate the test statistic. (Round your answer to two decimal places.) What is the p-value? (Round your answer to four decimal places.) p-value Using a 0.05 level of significance, what is your…

The U.S. Department of Labor stated that the national unemployment rate was 4.9%. Of a sample of 90 people in one city, 5.2% were unemployed. Can the city conclude that their unemployment rate is the same as the national average? Do we reject the null hypothesis? (Answer on Excel)