Question

Question 19 1 pts Given a population in which the probability of success is p=0.50, if a sample of 200 items is taken, Calculate the probability the proportion of successes in the sample will be between 0.46 and 0.53. (Round to four decimal places as needed.) 1 pts Question 20 What sample size is needed to estimate a population mean within plus or minus 70 of the true mean value using a confidence level of 90%, if the true population variance is known to be 140,625?

Answer 1

sdutto (la normal distribution with Caven, Sample proportion Å follows a up = p = 0.50 Standard deviation T mean P(1-P) Tour 0.50 X 0.50 200 0.03535 Now ! . Ploub c p < 0.53)UNA p(a.u6 cp 2053) p ( 0.46 up Тр To Lave Pega P > p (-1.1315 Þ( -_1315 2 2 2 0.8486) > p (2 2 0.8486 ) -p(? 0.53-Up - up 2 Ts 0.53 -0.50 0.03535 0.46 -0.50 L Z L 0.03535 L-1.1315 0.801948 -0.1289224 = 0.6730 20 ) Coren population variance 140625 140625 375 = 70 margin of Good E Confidence Intence & 90. 1-0.90 - 0.10 now find Critical value of zal = 1.645 sample size: ( 24 x ) = 1.645 * 375) n. 2 = "17.660 18 20 no 78 Sample size