Question

A random sample of 225 adults was given an IQ test. It was found that 105 of them scored higher than 100. Based on this, compute a 90% confidence interval for the proportion of all adults whose IQ score is greater than 100. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to two decimal places. What is the lower limit of the 90% confidence interval? What is the upper limit of the 90% confidence interval? xs ?

Answer 1

Solution ! Given that x =105 n = 225 - m = 109 - 04 66 1 - 0 - 44 46. 225 At '2' is got. conficlence level 2 l-90-. 2 - 1 - 0.90 di 2 = 0-1/2 = 0.05 2212 - 2005 = 10645 At is, got. confidence interucel for proportion e + 2212 X Ê CI- Ê J - V n 0.466 ± 1.645 x 0.466 (1-0.466) 225 0.4667 0.055 To.41, 0.52) Lower limit of go% confidence upper limit of gol confidence interval = 0.41 interval = 0.52