1a) Find x 2 left and x 2 right for a 95% confidence interval using the chi-square distribution with 9 degrees of freedom. b) What is the 90% confidence interval for the variance of exam scores for 28...

1a) Find x²left and x²right for a 95% confidence interval using the chi-square distribution with 9 degrees of freedom.

b)  What is the 90% confidence interval for the variance of exam scores for 28 algebra students, if the standard deviation of their last exam was 12.7?

Answer all parts of the question, 1a and 1b. Thanks.