Question

Periodically, the county Water Department tests the drinking water of homeowners for contaminants such as lead and copper. The lead and copper levels in water specimens collected in 1998 for a sample of 10 residents of a subdevelopement of the county are shown below.

lead (μ

g/L) copper (mg/L)

5.8

0.36

2.8

0.825

5.3

0.285

2.7

0.157

0.9

0.339

0.6

0.147

2

0.407

4

0.081

4.7

0.261

4.2

0.762

Round all values to at least four decimal places.

(a)

Construct a 99

% confidence interval for the mean lead level in water specimens of the subdevelopment:

We are 99

% sure that ≤μ≤

.

(b)

Construct a 99

% confidence interval for the mean copper level in water specimens of the subdevelopment:

We are 99

% sure that ≤μ≤

.

Answer 1

The solution is done showing all steps with necessary explanations. For your better understanding a t table is also attached. Hope you will have no problem understanding it.

t table -