A laboratory claims that the mean sodium level, μ, of a healthy adult is 139 mEq per liter of blood. To test this claim, a random sample of 90 adult patients is evaluated. The mean sodium level for the sample is 141 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 12 mEq. Can we conclude, at the 0.01 level of significance, that the population mean adult sodium level differs from that claimed by the laboratory?
Perform a two-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 a list of formulas.)
The null hypothesis:
H0:
The alternative hypothesis:
H1:
The type of test statistic:
(Choose one)ZtChisquareF
The value of the test statistic:
(Round to at least three decimal places.)
The two critical values at the 0.01 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
