Answer to Question #320221 in Statistics and Probability for hoon

Question

1. A study of 40 SHS English teachers established that they spent 12.6 minutes revising a student’s term paper.

- Find the 90% confidence interval in the mean time for all composition papers when minutes.

- If the teacher affirmed that she spent an average of 30 minutes revising a term paper, what would be your reaction?

2. Find the sample size to estimate a population mean within 95% confidence if the standard deviation is 6.2.

3. The prices for LED are listed: 22 500, 24 000, 21 500, 20 200, 20 600, 21 100, 210 000, 19 300, 25 000 and 22 500. Estimate the true mean of the data set with 90% confidence level.