Question

In a test of the effectiveness of garlic for lowering​ cholesterol, 445 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol​ (in mg/dL) have a mean of 33.5 and a standard deviation of 18.2. Complete parts​ (a) and​ (b) below. Click here to view a t distribution table. LOADING... Click here to view page 1 of the standard normal distribution table. LOADING... Click here to view page 2 of the standard normal distribution table. LOADING... a. What is the best point estimate of the population mean net change in LDL cholesterol after the garlic​ treatment? The best point estimate is 3.5 ​mg/dL. ​(Type an integer or a​ decimal.) b. Construct a 90 90​% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL​ cholesterol? What is the confidence interval estimate of the population mean mu μ​? negative −1.22 ​mg/dL less than < mu μ less than < 8.22 ​mg/dL ​(Round to two decimal places as​ needed.)

Answer 1

sample mean sample size population std deviation 33.50 생생%.(X) 18.200 standard errror of mean Ξσ,-σ//n_ 0.8628 for 90 % CI value of margin of error E-z*std error lower confidence bound-sample mean-margin of error Upper confidence bound-sample mean +margin of error 1.419 32.08 34.92

from above "

best point estimate is =33.50

90​% confidence interval estimate of the mean net change in LDL cholesterol =32.08 to 34.92