Chapter 19, Problem 28E

(a)

To determine

To find out how many patients’ results must be used.

Answer to Problem 28E

  $829$ .

Explanation of Solution

It is given in the previous question that in San Diego reproductive clinic reported live births to women under age of $40$ who had previously been unable to conceive. Thus, the clinic wants to cut the stated margin of error in half. So, the number of patients’ results that must be used can be calculated as:

  $\begin{array}{l}ME=1.645\times \sqrt{\frac{0.237\times 0.763}{207}}\\ =0.0486\\ M{E}_N=\frac{0.0486}{2}\\ =0.0243\\ \text{Thus, }0.0243=1.645\times \sqrt{\frac{0.237\times 0.763}{n}}\\ \text{Solve for }n\\ \Rightarrow 0.0148=\sqrt{\frac{0.237\times 0.763}{n}}\\ \Rightarrow n=829\end{array}$

Thus, $829$ patients’ results must be used in this.

(b)

To determine

To explain do you have any concerns about this sample.

Answer to Problem 28E

Yes, there is.

Explanation of Solution

It is given in the previous question that in San Diego reproductive clinic reported live births to women under age of $40$ who had previously been unable to conceive. Thus, yes, there is a concern with the sample because this sample is likely not random or representative.