To assess the accuracy of a laboratory scale, a standard weight that is known to weigh 1 gram is repeatedly weighed a total on n times and the mean of x of the weighing is completed. Suppose the scale readings are j BJ or ally distributed with unknown mean u And the standard deviarion a= 0.01g. How large should n be so that a 95 % confidence interval for u has a margin of error of error of +|- 0.001?

To compare the dry braking distances from 30 to 0 miles per hour for two makes of​ automobiles, a safety engineer conducts braking tests for 35 models of Make A and 35 models of Make B. The mean braking distance for Make A is 43 feet. Assume the population standard deviation is 4.6 feet. The mean braking distance for Make B is 46 feet. Assume the population standard deviation is 4.5 feet. At α=0.10​, can the engineer support the claim that the mean braking distances are different for the two makes of​ automobiles? Assume the samples are random and​ independent, and the populations are normally distributed.   The critical​ value(s) is/are   Find the standardized test statistic z for μ1−μ2.

In the year 2033, Sarai Patterson is a leading traveling nurse. Sarai is interested in reducing the mean recovery time for patients after experiencing a serious injury (assume recovery times are normally distributed). Suppose the mean recovery time is presently 8.6 months. Sarai takes a random sample of 46 patients that have experienced serious injury to participate in a new treatment program and finds the sample mean is 8.1 months and a sample standard deviation of 1.2 months. Using α = 0.05, answer the following questions. a) What is the setup for your null and alternative hypothesis? b) What is the value of the test statistic? c) What is/are the critical value(s)?

C. Given a and the z-values. Indicate whether the decision is to reject the null hypothesis or accept the null hypothesis for each of the following. Use a = .05 0.05, z = 2.5, two-tailed 9. a – 0.05, z = -1.645, one-tailed 10. a – 0.01, z = -3.7, two-tailed 8. a –

In order to construct a confidence interval for the population variance, a random sample of n observations is drawn from a normal population. Use this information to find x²a/2, df and x²1-a/2, df under the following scenarios. (Round your answers to 3 decimal places. You may find it useful to reference the appropriate table: chi-square table or Ftable) X²al2,df a. A 95% confidence level with n = 9. b. A 95% confidence level with n = 40. c. A 99% confidence level with n = 9. d. A 99% confidence level with n = 40. X²1-a/2,df

X. is found to be 19.1, and the A simple random sample of sizen is drawn from a population that is normally distributed. The sample mean, sample standard deviation, s, is found to be 4.9. (a) Construct a 96% confidence interval about u if the sample size, n, is 39. (b) Construct a 96% confidence interval about u if the sample size, n, is 68. How does increasing the sample size affect the margin of error, E? (c) Construct a 98% confidence interval about u if the sample size, n, is 39. How does increasing the level of confidence affect the size of the margin of error, E? (d) If the sample size is 14, what conditions must be satisfied to compute the confidence interval? (a) Construct a 96% confidence interval about u if the sample size, n, is 39. Lower bound: Upper bound: (Round to two decimal places as needed.) (b) Construct a 96% confidence interval about u if the sample size, n, is 68. Lower bound: ; Upper bound: (Round to two decimal places as needed.) How does increasing the sample…

An SRS of 20 orangutans is selected, and 65 cc of blood is to be drawn from each orangutan using a 100 cc syringe. In the sample, the mean volume is 64 cc and the standard deviation is 12 cc. Assume that in the population of all such procedures, the amount of blood drawn follows ą Normal distribution with mean u. A 90% confidence interval for the population mean volume based on these data is

A sample of n = 10 scores has M = 58, s =12.65, and an estimated standard error of 4 points. Which of these values will definitely decrease if the sample size is increased to n = 1007 Show answer choices v