Problem Page

Question

A laboratory claims that the mean sodium level,

, of a healthy adult is140

mEq per liter of blood. To test this claim, a random sample of30

adult patients is evaluated. The mean sodium level for the sample is139

mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is12

mEq. Assume that the population isnormally distributed.Can we conclude, at the0.05

level of significance, that the population mean adult sodium level differs from that claimed by the laboratory?

Perform atwo-tailed test. Then fill in the table below.

Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. (If necessary, consult alist of formulas.)

Thenull hypothesis:H

0

:

Thealternative hypothesis:H

1

:

The type oftest statistic:(Choose one)

Z

t

Chi square

F

The value of the test statistic:

(Round to at least three decimal places.)

The twocritical valuesat the0.05

level of significance:

(Round to at least three decimal places.)and

Can we conclude that the population mean adult sodium level differs from that claimed by the laboratory?

Yes

No