The mean replacement time for a random sample of 12 microwave ovens is 8.6 years with a standard deviation of 3.7 years. Construct the​ 98% confidence interval for the population​ variance, σ2. A. ​(5.744​,42.17​) B. ​(1.646​,13.331​) C. ​(2.468​,7.023​) D. ​(6.091​,49.325​)

The average life of light bulbs produced by SABA Electric Co. is expected to be normally distributed with the mean service life of 950 hours and standard deviation of 100 hours. A consumer agency tests a random sample of 100 bulbs and finds mean service life of 910 hours. If the agency conducts hypothesis testing, what would be the computed p-value for the test? 4 10 0% 3.49 none of the above.

The results of a state mathematics test for random samples of students taught by two different teachers at the same school are shown below. Can you conclude there is a difference in the mean mathematics test scores for the students of the two teachers?                                                                                                                                                                                                                                                                    Use α = 0.01. In addition, assume the populations are normally distributed and the population variances/standard deviations are not equal.   Teacher 1 Teacher 2 ?̅1 =  473 ?̅2 = 459 S1 = 39.7 S2 = 24.5 n 1 = 8 n 2 = 18   a. State the null and alternate hypotheses (write it mathematically) and write your claim.   b. Find the test statistic        c. Identify the Rejection region (critical region) and fail to reject region. Show this by drawing a curve and…

53.305) B. (24.591, 35.563) C. (26.591, 37.563) D. (28.591, 39.563) 34. A simple random sample of size n = 36 is taken from a normally distributed original population. The sample standard deviation iss = 7. Find the 99% confidence interval for the population variance o2. A. (27.453, 98.756) B. (28.453, 99.756) C. (29.453, 100.756) D. (30.453, 101.756)

A random sample of 10 subjects have weights with a standard deviation of 11.9848 kg . What is the variance of their weights ? Be sure to include the appropriate units with the result .

A random sample of 10 subjects have weights with a standard deviation of 12.7436 kg. What is the variance of their weights? Be sure to include the appropriate units with the result. The variance of the sample data is (Round to four decimal places as needed.)

Only need help with finding tcalc.

A sample of n = 9 scores has a variance of s2 = 144. What is the standard deviation for this sample?