Find the critical value z that α 2 corresponds to the confidence level 87%. Z = (Round to two decimal α 2 places as needed.) K Find the critical value za/2 that corresponds to the confidence level 87%. Za/2= (Round to two decimal places as needed.)

Given that X̄=20, σ=9 and n=81, construct the following confidence intervals: the 90% confidence interval for μ is:  a (18.355, 21.645)   b (18.040, 21.960) c (17.840, 36.450) d (18.750, 23.450)

A manufacturer of cell phone batteries wants to estimate the useful life of it'sthe battery (in thousand of hours.) The estimate is the be within 0.10 (100) hours.Assume a 95 percent level of confidence and that the standard deviation of theuseful life of the battery is 0.90 (900 hours). Determine the required sample size.

The body temperatures in degrees Fahrenheit of a sample of adults in one small town are: 97.8 97 97.5 99.1 98.4 97.9 97.7 Assume body temperatures of adults are normally distributed. Based on this data, find the 80% confidence interval of the mean body temperature of adults in the town. Enter your answer as an open-interval (i.e., parentheses) accurate to 3 decimal places. Assume the data is from a normally distributed population.80% C.I. =

The correct answer is C. Please prove the result mathematically.

Tom wants to estimate the percentage of students who live more than 3 miles from the school.He wants to create a 95% confidence interval which has a margin of error of at most 3% .How many students must be polled to create the confidence interval?

sssss A consumer affairs investigator records the repair cost for 4 randomly selected TVs. A sample mean of $75.89 and standard deviation of $13.53 are subsequently computed. Determine the 80% confidence interval for the mean repair cost for the TVs. Assume the population is approximately normal. Step 1 of 2: Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

A chemist measures the haptoglobin concentrations (in grams per liter) in the blood of eight healthy adults. The mean and standard deviation of the haptoglobin concentrations (in grams per liter) are 1.615 and 1.387 respectively. Obtain a 90% confidence interval for the mean haptoglobin concentration in adults.

Economic Q7 onlys

a. 36 Out of 100 persons interviewed are familiar with the tax incentive given by the governmenti for installing solar panel, construct 96% confidence interval for true proportion. b. The average wages of 25 employees of a company are RS. 2500 with standard deviation of Rs. 250. Assuming wages to be normally distributed, calculate 98% confidence upper bound for the average wages and interpret it.