Question 1014767: Two-tailed test; 0.10
o Assume that the normal distribution applies and find the critical z values.
• Use the following information to find the P-value.
o The value of the test statistic for a right-tailed one mean z test is z = 2.50.
Use a 0.05 significance level and state the conclusion about the null hypothesis—reject the null hypothesis or fail to reject the null hypothesis.
• Test the claim: A simple random sample of 50 adults is obtained, and each person’s red blood cell count (in cells per micro-liter) is measured. The sample mean is 5.23. The population standard deviation for red blood cell counts is 0.54. Use a 0.01 significance level to test the claim that the sample is from a population with a mean less than 5.4, which is a value often used for the upper limit of the range of normal values. What do the results suggest about the sample group?
• Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical value(s), conclusion about the null hypothesis, and the conclusion that addresses the original claim. Use the P-value method.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Two-tailed test; 0.10
o Assume that the normal distribution applies and find the critical z values.
Ans:: z = +/- 1.645
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• Use the following information to find the P-value.
o The value of the test statistic for a right-tailed one mean z test is z = 2.50.
Ans: p-value = p(z > 2.5) = normalcdf(2.5,100) = 0.006
Use a 0.05 significance level and state the conclusion about the null hypothesis—reject the null hypothesis or fail to reject the null hypothesis.
Ans: Since the p-value is less than 5%, reject Ho.
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• Test the claim: A simple random sample of 50 adults is obtained, and each person’s red blood cell count (in cells per micro-liter) is measured. The sample mean is 5.23. The population standard deviation for red blood cell counts is 0.54. Use a 0.01 significance level to test the claim that the sample is from a population with a mean less than 5.4, which is a value often used for the upper limit of the range of normal values. What do the results suggest about the sample group?
Ho: u >= 5.4
Ha: u < 5.4 (claim)
x-bar = 5.23
test statistic = z(5.23) = (5.23-5.4)/[0.54] = -4.77
p-value = P(z < -4.77) = 0.000000092
Since the p-value is less than 1%, reject Ho.
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The test results support the claim.
Cheers,
Stan H.
• Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical value(s), conclusion about the null hypothesis, and the conclusion that addresses the original claim. Use the P-value method.
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Cheers,
Stan H.
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