In a sample of 42 water specimens taken from a construction site, 26 contained detectable levels of lead. Construct a 95% condence interval for the proportion of water specimens that contain detectable levels of lead

The 95% confidence interval for the proportion of water specimens that contain detectable levels of lead is (0.472,0.766).

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 .

In a sample of 42 water specimens taken from a construction site, 26 contained detectable levels of lead.

This means that

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 water specimens that contain detectable levels of lead is (0.472,0.766).

0.50 , 0.75

step-by-step explanation:

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x