A union of restaurant and foodservice workers would like to estimate the mean hourly wage, H, of foodservice workers in the U.S. The union will choose a random sample of wages and then estimate u using the mean of the sample. What is the minimum sample size needed in order for the union to be 99% confident that its estimate is within $0.40 of u? Suppose that the standard deviation of wages of foodservice workers in the U.S. is about $2.10. Carry your intermediate computations to at least three decimal places. Write your answer as a whole nuhber (and make sure that it is the minimum whole number that satisfies the requirements).

The amount of time adults spend watching television is closely monitored by firms because this helps to determine advertising pricing for commercials. Complete parts (a) through (d). ..... (b) According to a certain survey, adults spend 2.35 hours per day watching television on a weekday. Assume that the standard deviation for "time spent watching television on a weekday" is 1.93 hours. If a random sample of 60 adults is obtained, describe the sampling distribution of x, the mean amount of time spent watching television on a weekday. x is approximately normal with H = 2.35 and o- = 0.249162. (Round to six decimal places as needed.) (c) Determine the probability that a random sample of 60 adults results in a mean time watching television on a weekday of between 2 and 3 hours. The probability is 0.9154 . (Round to four decimal places as needed.) (d) One consequence of the popularity of the Internet is that it is thought to reduce television watching. Suppose that a random sample of 55…

The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1775 pounds and a standard deviation of 70 pounds. The company believes that, due to an improvement in the manufacturing process, the mean breaking strength, u, of the cables is now greater than 1775 pounds. To see if this is the case, 14 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1812 pounds. Assume that the population is normally distributed. Can we support, at the 0.10 level of significance, the claim that the population mean breaking strength of the newly- manufactured cables is greater than 1775 pounds? Assume that the population standard deviation has not changed. Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.) (a) State the null hypothesis H, and the…

Assume the average amount of caffeine consumed daily by adults is normally distributed with a mean of 260 mg and a standard deviation of 48 mg. In a random sample of 600 ​adults, how many consume at least 320 mg of caffeine​ daily?

Manatees are one creature found in coastal waterways. 10 years ago, researchers concluded that the true mean weight of manatees was approximately 1050 lbs. This year, a random sample of 12 manatees were selected, the sample weights are: 956, 1012, 954, 988, 973, 1048, 1075, 1064, 856, 1026, 1031, 1064. Assume the underlying distribution of manatee weights is normal, and population standard deviation o is unknown.  Implement a hypothesis test to verify if there is any evidence to suggest the true mean weight decreases now. Solve the hypothesis using P-value method. Let a = 0.05. . Use the given sample data to calculate 90% confidence interval for true mean weight of manatees.

A consumer advocacy group is doing a large study on car rental practices. Among other things, the consumer group would like to estimate the mean monthly mileage, µ, of cars rented in the U.S. over the past year. The consumer group plans to choose a random sample of monthly U.S. rental car mileages and then estimate u using the mean of the sample. Using the value 850 miles per month as the standard deviation of monthly U.S. rental car mileages from the past year, what is the minimum sample size needed in order for the consumer group to be 90% confident that its estimate is within 175 miles per month of u? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements). (If necessary, consult a list of formulas.)

Suppose that water usages in American showers are normally distributed, with an average shower using 20 gallons, and a standard deviation of 3.2 gallons. Estimate the percentage of showers that used (a) between 13.6 and 26.4 gallons. % (b) more than 26.4 gallons. % (c) less than 10.4 gallons. % (d) between 16.8 and 29.6 gallons. %

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 consumer advocacy group is doing a large study on car rental practices. Among other things, the consumer group would like to estimate the mean monthly mileage, μ, of cars rented in the U.S. over the past year. The consumer group plans to choose a random sample of monthly U.S. rental car mileages and then estimate μ using the mean of the sample.Using the value 750 miles per month as the standard deviation of monthly U.S. rental car mileages from the past year, what is the minimum sample size needed in order for the consumer group to be 99% confident that its estimate is within 135 miles per month of μ? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements).

A consumer advocacy group is doing a large study on car rental practices. Among other things, the consumer group would like to estimate the mean monthly mileage, μ, of cars rented in the U.S. over the past year. The consumer group plans to choose a random sample of monthly U.S. rental car mileages and then estimate u using the mean of the sample. Using the value 700 miles per month as the standard deviation of monthly U.S. rental car mileages from the past year, what is the minimum sample size needed in order for the consumer group to be 99% confident that its estimate is within 175 miles per month of μ? Carry your intermediate computations to at least three decimal places. Write your answer as a whole number (and make sure that it is the minimum whole number that satisfies the requirements). (If necessary, consult a list of formulas.) 0 X S