Question 366576
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14.
a.)  {{{525/1230 +- 2.325sqrt(((525/1230)*(705/1230))/1230)}}}. This corresponds to the open interval (0.39404, 0.45962).
b.) No, it is not reasonable to conclude from the sample that the president is doing a good job.  In fact we could say that the true proportion may be less than 50%. (As opposed to the null hypothesis that the true proportion is equal to or greater than 50%.)

15.
a.)  $63/hr.
b.) Using the t-distribution  with 22 degrees of freedom, the C.I. is {{{63+- (2.508)*(6.1/sqrt(23))}}}.  This corresponds to the open interval (59.81, 66.19).
c.)We use the standard normal table again.   We want {{{1>=1.645*(6.1/sqrt(n))}}}.  This should give {{{sqrt(n)>=10.0345}}}, or {{{n>=100.69}}}.  We can put n = 101.