Answer:
The point estimate for the proportion is p = 0.4725
The 95% confidence interval for the proportion of non-fatal accidents that involved the use of a cell phone is (0.4236, 0.5214).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence level of , we have the following confidence interval of proportions.
In which
z is the zscore that has a pvalue of .
For this problem, we have that:
Point estimate
95% confidence level
So , z is the value of Z that has a pvalue of , so .
The lower limit of this interval is:
The upper limit of this interval is:
The 95% confidence interval for the proportion of non-fatal accidents that involved the use of a cell phone is (0.4236, 0.5214).