

a-c please 2. A random sample of 144 checking accounts at a bank showed an average...
A random sample of 144 checking accounts at a bank showed an average daily balance of $295. The standard deviation of the population is known to be $72. Please answer the following questions: (a) Find the standard error of the mean. (b) Give a point estimate of the population mean. (c) Construct a 95% confidence interval estimates for the mean.
Patty, a branch manager of a bank, would like a quick estimate of the mean checking account balance of all checking account customers. A random sample of checking 32 account balances results in a sample mean of $312,590.50 and a standard deviation of $52,100. Calculate and interpret a 95% confidence interval for the mean checking account balance. Round off all answers to two decimal places with complete solutions.
9. A simple random sample of 37 weights of pennies made after 1983 has a sample mean of 2.4991 g and a known population standard deviation of 0.0165 g. a. Construct a 99% confidence interval estimate of the mean weight of all such pennies. b. Design specifications require a population mean of 2.5 g. What does the confidence interval suggest about the manufacturing process? 10. A random sample of 40 students has a mean annual earnings of $3120 and a...
A pediatrician's records showed the mean height of a random sample of 25 girls at age 12 months to be 29.530 inches with a standard deviation of 1.0953 inches. Construct a 95% confidence interval for the population variance. (Round your answers to 4 decimal places.) The 95% confidence interval is from____ to ____
a simple random sample of 26 college students showed a mean credit score of 575 and a standard deviation 10. construct the 90% confidence interval estimate of the mean credit score for all college students a. state the critical value b. compute the margin of error c. state the confidence interval
2. A simple random sample of 15 college students showed a mean credit score of 655 and standard deviation 20. Construct the 99% confidence interval estimate of the mean credit score for all college students. a. State the critical value. b. Compute the margin of error. c. State the confidence interval.
1. A random sample of 82 customers, who visited a department store, spent an average of $71 at this store. Suppose the standard deviation of expenditures at this store is O = $19. What is the e 98% confidence interval for the population mean? 2. A sample of 25 elements produced a mean of 123.4 and a standard deviation of 18.32 Assuming that the population has a normal distribution, what is the 90% confidence interval for the population mean? 3....
-0.07 0.07 z 2. A bank has kept records of the checking balances of its customers and determined that the average daily balance of its customers is $300 with a standard deviation of $48, and is a normally distributed population. A random sample of 144 checking accounts is selected a) What is the probability that the sample mean will be at least $306.60? b) What is the probability that the sample mean will be less than $308? c) What is...
the average selling price of a smartphone purchased by a random sample of 46 customers was $317. Assume the population standard deviation was $32. a) Construct a 95% confidence interval to estimate the average selling price in the population with this sample. b) What is the margin of error for this interval?
6.2.19-T Question Help In a random sample of four microwave ovens, the mean repair cost was $85.00 and the standard deviation was $13.00. Assume the population is normally distributed and use a t-distribution to construct a 99% confidence interval for the population mean μ. What is the margin of error of μ? Interpret the results. The 99% confidence interval for the population mean μ is (DD (Round to two decimal places as needed.) 6.2.21-T Question Help In a random sample...