A political action committee is interested in finding out what proportion of voters will

support an environmental initiative. Obtain a sample size that will ensure a margin of

error of at most 0.09 for a 95% confidence interval. Similar initiatives in the past have

gotten 93% support.

And rounded up we have that n=31

Step-by-step explanation:

First we need to find the critical value for the margin of error desired. The confidence level is 0.95 so then the significance is and the critical value for this case would be:

The margin of error for the proportion interval is given by this formula:  

   (a)  

And on this case we have that and we are interested in order to find the value of n, if we solve n from equation (a) we got:  

  (b)  

The estimated proportion for this case is . And replacing into equation (b) the values from part a we got:

And rounded up we have that n=31