Question

A laboratory claims that the mean sodium level, μ, of a healthy adult is 138 mEq per liter of blood. To test this claim, a random sample of 43 adult patients is evaluated. The mean sodium level for the sample is 144 mEq per liter of blood. It is known that the population standard deviation of adult sodium levels is 14 mEq. Assume that the population is normally distributed. Can we conclude, at the 0.05 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:

The alternative hypothesis:

The type of test statistic:

The value of the test statistic (rounded to at least 3 decimal places):

The two critical values at the 0.05 level of significance: (rounded to at least 3 decimal places):

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

Answer 1