You may need to use the appropriate appendix table or technology to answer this question.

Two hundred students are enrolled in an Economics class. After the first examination, a random sample of 6 papers was selected. The scores were 63, 69, 84, 66, 67, and 77.

(a)

Determine the standard error of the mean. (Round your answer to four decimal places.)

(b)

What assumption must be made before we can determine an interval for the mean score of all the students in the class? Explain why.

Since the distribution of all scores is not normal we must assume = s.Since n is small and is estimated from s, we must assume that s is greater than n. Since n is small and is estimated from s, we must assume that n is greater than s.Since n is small and is estimated from s, we must assume that x is greater than s.Since n is small and is estimated from s, we must assume the distribution of all the scores is normal.

(c)

Assume the assumption of Part b is met. Provide a 95% confidence interval for the mean score of all the students in the class. (Round your answers to two decimal places.)