URGENT!!! PLEASE:If n=21, x bar=41, and s=6, construct a confidence interval at a 99% confidence level. Give your answers to one decimal place.

Question

If n=21, x bar=41, and s=6, construct a confidence interval at a 99% confidence level. Give your answers to one decimal place.

 < μ <

Answer 1

mean-zs/sqrn < mean<mean+ zs/sqrn

mean=41, s=6, n=41

z=about 3 by the empirical rule, for 99% confidence interval (actually 99.7%)

zs/sqrn=3(6)/sqr41= about 18/sqr21= about 3.9

37.1 < population mean < 44.9

or use z tables or z calculator instead of the empirical rule for a more accurate confidence interval

z=2.575

41-3.4<mean<41+3.4

37.6<mean<44.4

mean+/-3.4

(37.6, 44.4)