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. a. At the 0.05 level of significance, is there evidence that the mean life is different from 7,508 hours? b. Compute the p-value and interpret its meaning. c. Construct a 95% confidence interval estimate of the population mean life of the light bulbs. d. Compare the results of (a) and (c). What conclusions do you reach? a. Let u be the population mean. Determine the null hypothesis, H, and the alternative hypothesis, H,. Ho: H =

A supplier is selling lumber to a building supply company.  The building supply company requires that the overall length of a particular type of board measure between 95.9 and 96.1 inches. Before sending its next shipment, the supplier collects a large sample of boards and determines the mean length of the sample is 96.03 inches, with a standard deviation of 0.029 inches. What is the process capability index of the current process? Two decimal places.

A​ half-century ago, the mean height of women in a particular country in their 20s was 62.3inches. Assume that the heights of​ today's women in their 20s are approximately normally distributed with a standard deviation of 2.25inches. If the mean height today is the same as that of a​ half-century ago, what percentage of all samples of 29of​ today's women in their 20s have mean heights of at least 63.41 inches?

A recent report indicates that 2-year-old children from the well-educated suburban families watched an average of m=60 minutes of television each day. Assuming that the distribution of television-watching times is normal with a standard deviation of 25 minutes, find each of the following proportions. a. What proportion of 2- year-old children watch more than two hours of television each day? b. what proportion of 2-year-old children watch less than 30 minutes a day?

A marketing researcher wants to estimate the mean amount spent per year​ ($) on a web site by membership member shoppers. Suppose a random sample of 100 membership member shoppers who recently made a purchase on the web site yielded a mean amount spent of ​$58and a standard deviation of ​$55.Complete parts​ (a) and​ (b) below. a. Is there evidence that the population mean amount spent per year on the web site by membership member shoppers is different from ​$51​? ​(Use a 0.01 level of​ significance.)   State the null and alternative hypotheses.

The Wall Street Journal reported that 33% of taxpayers with adjusted gross incomes between $30,000 and $60,000 itemized deductions on their federal income tax return. The mean amount of deductions for this population of taxpayers was $16.941. Assume that the standard deviation iso = $2942. Use z-table. a. What is the probability that a sample of taxpayers from this income group who have itemized deductions will show a sample mean within $176 of the population mean for each of the following sample sizes: 30, 50, 100, and 400? Round your answers to four decimals. n = 30 n = 50 n = 100 n = 400 b. What is the advantage of a larger sample size when attempting to estimate the population mean? Round your answers to four decimals. A larger sample - Select your answer the probability that the sample mean will be within a specified distance of the population mean. In this instance, the probability of being within +176 of µ ranges from for a sample of size 30 to for a sample of size 400. 0Icon…

A quick survey of peanut butter prices had standard deviation and mean of $.26 and $3.68 respectively. Compute the area for a peanut butter jar costing more than $4.25

In a school district, all sixth grade students take the same standardized test. The superintendant of the school district takes a random sample of 3030 scores from all of the students who took the test. She sees that the mean score is 169169 with a standard deviation of 7.06747.0674. The superintendant wants to know if the standard deviation has changed this year. Previously, the population standard deviation was 1313. Is there evidence that the standard deviation of test scores has decreased at the α=0.005α=0.005 level? Assume the population is normally distributed. Step 1 of 5:  State the null and alternative hypotheses. Round to four decimal places when necessary. Step 2 of 5:  Determine the critical value(s) of the test statistic. If the test is two-tailed, separate the values with a comma. Round your answer to three decimal places.     Step 3 of 5:  Determine the value of the test statistic. Round your answer to three decimal places. Step 4 of 5:  Make the…

An air condition company will spend an average of 64 minutes with a standard deviation of 19 minutes on a service call. Based on this, and assuming a normal distribution, 5% of service calls will take more than how much time to complete? Approximately 66.29 minutes O Approximately 32.75 minutes O Approximately 39.41 minutes O Approximately 95.25 minutes O Approximately 77.23 minutes

Suppose the mean number of candies in a standard vending machine bag is 47.6 with a standard deviation of 1.3 . assume that the number of candies is normally distributed what percentage of bags have less than 45 candies?