Question

Assume that a sample is used to estimate a population mean μμ. Find the 80% confidence interval for a sample of size 457 with a mean of 66.5 and a standard deviation of 13.4. Enter your answer as a tri-linear inequality accurate to 3 decimal places.
____ < μ < ____

Answer 1

Solution Given that ř = 66.5 8 = 13.4 At 80% confidence level o = 1- 80% = 1- 0.8 = 0.2 a 0.2 0.1 2 2 2012 - 20. = 1.282 Margin of foror: 2012. Xo o = 1.282 X 13.5 457 E = 0.804 At 80% confidence interval estimote of the population meon is X-Ecer xt 66.5-0.804 <uk 66.5 +0.804 65.694 < < 67.304 (65.694, 67.304 ) 65.69:4 < u2 67. 304