Studies have shown that drivers who use cell phones while operating a motor passenger vehicle increase their risk of an accident. Nevertheless, drivers continue to make cell phone calls while driving. A June 2011 Harris Poll of 2,163 adults found that 64% use cell phones while driving.

a.Give a point estimate of p, the true driver cell phone use rate (i.e., the proportion of all drivers who are using a cell phone while operating a motor passenger vehicle).

b.Find a 90% confidence interval for p.

c.Give a practical interpretation of the interval, part b.

d.Is it reasonable to stat that more than half of the drivers use cell phones while driving?