D Question 7 1 pts Find Za/2 for the 99% confidence interval. D Question 8 1 pts Find Za/2 for the 94% confidence interval. D Question 9 1 pts The term Za/2(-) is called [ Select ] D Question 10 1 pts The length of the confidence interval is always equal to [ Select ] times of the margin of error. D Question 11 1 pts Since later on we will be referring to this problem, let us call it EXERCISE 1. A random sample of 36 exam scores is taken from the normally distributed population with unknown mean and a populations standard deviation know and equal to 3. The sample mean score is 68. Find a 90% confidence interval estimate for the population mean of exam scores. Please round to the nearest hundredths and write your answer in the form ( , ); for example (31,34) or (25,46). Do not type in any extra spaces. D Question 12 1 pts A random sample of 36 exam scores is taken from the normally distributed population with unknown mean and a populations standard deviation know and equal to 3. The sample mean score is 68. Find a 95% confidence interval estimate for the population mean of exam scores. Please round to the nearest hundredths and write your answer in the form ( , ); for example (31,34) or (25,46). Do not type in any extra spaces. (notice that the only difference between this question and EXERCISE 1 is the change in the confidence level; is the new confidence interval narrower or wider?)