Given two independent random samples with the following results: n1=13x‾1=149s1=27n1=13x‾1=149s1=27   n2=13x‾2=167s2=15n2=13x‾2=167s2=15 Use this data to find the 90%90% confidence interval for the true difference between the population means. Assume that the population variances are equal and that the two populations are normally distributed.   Step 1 of 3 :   Find the point estimate that should be used in constructing the confidence interval.

A sample of size 50 from a normal distribution has sample mean 5 and sample variance 20. Find 96% confidence intervals for the variance and standard deviation of the distribution.

A light bulb manufacturer wants to compare the mean lifetimes of two of its light bulbs, model A and model B. Independent random samples of the two models were taken. Analysis of 15 bulbs of model A showed a mean lifetime of 1348 hours and a standard deviation of 81 hours. Analysis of 11 bulbs of model B showed a mean lifetime of 1351 hours and a standard deviation of 109 hours. Assume that the populations of lifetimes for each model are normally distributed and that the variances of these populations are equal. Construct a 99% confidence interval for the difference H-, between the mean lifetime u, of model A bulbs and the mean lifetime u, of model B bulbs. Then find the lower limit and upper limit of the 99% confidence interval, Carry your intermediate computations to at least three decimal places. Round your responses to at least two decimal places. (If necessary, consult a list of formulas.) Lower limit: Upper limit: Explanation Check 2021 McGraw-Hill Education. Al Rights Reserved…

At age 9 the average weight for both boys and girls are exactly the same. A random sample of 9 year olds gave the following results....                                   Boys:                Girls:Sample Size:               65                     50Mean weight (lbs):      130                   125Pop. Variance:            120                   130 At alpha 0.05, do the data support the claim that there is a difference in heights?