18 A simple random sample of size n is drawn The sample mean

18) A simple random sample of size n is drawn. The sample mean, x, is found to be 17.9, and the sample standard deviation, s, is found to be 4.7

c) construct a 99% confidence interval about u if the sample size, n, is 34

The confidence interval is ( _,_)

(Use ascending order. Round to two decimal places as needed.)

d) If the sample size is 18, what conditions must be satisfied to compute the confidence interval?

a) the sample data must come from a population that is normally distributed with no outliners.

b) The sample size must be large and the sample should not have any outliners.

c) The sample must come from a population that is normally distributed and the sample size must be large.

So the lower bound is

xbar - Z*s/vn =17.9 - 2.58*4.7/sqrt(34) = 15.82

So the upper bound is

xbar + Z*s/vn =17.9 + 2.58*4.7/sqrt(34) =19.98

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(d) c) The sample must come from a population that is normally distributed and the sample size must be large.