Question

A study found that 6.7% of working Americans have worked at Mcdonalds. Let X represent the number of working Americans in a random sample of 900 Americans, who have worked at Mcdonalds. Find the mean and the standard deviation of X In a random sample of 900 working Americans, would it be unusual to find 65 of them have worked at Mcdonalds? Justify your answered

Answer 1

p=0.067 , n=900 Mean - da np - 900x0.067 = 160.3 ) standard deviation oodaplepy EN9000'067*(1-0.067) 7.5006 = -17.504. foon Normal approximation to Binomial axa Blaip) a (no) Proteon using coortiouity convention , P(x265 ) - pl 65-05 LX 5 65+0.5) - P(64.5 < x265-5) 2 PC 64.5 - 603 27C655 -603) = pl 0.56 CZC 069), - P(Z < 0.69) - P(240:56) = 0.7549 - 0-7123 =|6-0426] Yes, to find 65 of theran is unsual, because the probability 0.0426 <0.05 7.501 7.501