A 1999 General Accounting Office (GAO) study found that about a third of the 23.4 million retirees 65 or...?

A 1999 General Accounting Office (GAO) study found that about a third of the 23.4 million retirees 65 or older supplemented Medicine with some form of employee coverage the article suggests that this proportion is increasing. Suppose that in a current study, a random sample of 500 retirees 65 or older indicated that 185 supplemented Medicare with some form of employer coverage. At the 0.01 level of significance, is there evidence that the proportion of retirees 65 or older that supplement Medicare with some form of employer coverage is now greater than one-third?|||It has been awhile for me, so check my work, but...





Hypotheses: the proportion of retirees 65 or older that supplement Medicare with some form of employer coverage is now greater than one-third





Original p=1/3, q=2/3, so ave=N*1/3=500/3=167, sd=(500*1/3*2/3)^.5=10.5





So find if 185 falls into the upper .01 tail. This is z score of (185-167)/10.5=18/10.5=1.714





This is 1-.96=.04, which is not low enough for .01 level





Conclusion: The evidence does not support the hypothesis.