Question

Periodically, a town water department tests the the drinking water of homeowners for contaminants such as lead. The lead levels in water specimens collected for a sample of 10 residents of the town had a mean of 3.1 mg/L and a standard deviation of 1.6 mg/L. Complete parts a through c.

a.Construct a 90​% confidence interval for the mean lead level in water specimens from the town.

left parenthesis nothing comma nothing right parenthesis,

​(Round to three decimal places as​ needed.)

b. Interpret the interval in terms of this application. Choose the correct answer below.

A.The water department is confident that 90​% of the mean lead level in drinking water for all residents in the town is described by this interval.

B.The water department can be 90​% confident that the mean lead level in drinking water for all residents in the town is outside this interval.

C.The water department can be 90​% confident that the mean lead level in drinking water for all residents in the town is 3.1 ​mg/L.

D.The water department can be 10​% confident that the mean lead level in drinking water for all residents in the town is within this interval.

E.The water department can be 90​% confident that the mean lead level in drinking water for all residents in the town is within this interval.c. What is meant by the phrase "90​% confidence​ interval"?The phrase "90​% confidence​ interval" means that if many intervals were constructed using the same methods and the same

▼

sample variance,

sample mean,

sample standard deviation,

population standard deviation,

population mean,

sample size,

population variance,

then

​%

of those intervals would contain the true

▼

population mean.

population variance.

population standard deviation.

sample size.

sample mean.

sample variance.

sample standard deviation.

Click to select your answer(s).

Answer 1