SOLUTION: A laboratory claims that the mean sodium level, μ, of a healthy adult is 140 mEq per liter of blood. To test this claim, a random sample of 70 adult patients is evaluated. The mea

Algebra ->  Probability-and-statistics -> SOLUTION: A laboratory claims that the mean sodium level, μ, of a healthy adult is 140 mEq per liter of blood. To test this claim, a random sample of 70 adult patients is evaluated. The mea      Log On


   

Question 1150237: A laboratory claims that the mean sodium level, μ, of a healthy adult is 140 mEq per liter of blood. To test this claim, a random sample of 70 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 15 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?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
Ho: mean is 140
Ha: mean NE 140
alpha=0.01 p{reject Ho|Ho true}
test stat is a z (x bar-mean)/sigma/sqrt(n)
critical value is |z|>2.576
calculation is z=(141-140)/15/sqrt(70)= 1*sqrt(70)/15
=0.56
fail to reject Ho
insufficient evidence that mean is not 140 mEq