Question

In: Statistics and Probability

A random sample of 50 measurements resulted in a sample mean of 62 with a sample...

A random sample of 50 measurements resulted in a sample mean of 62 with a sample standard deviation 8. It is claimed that the true population mean is at least 64.

a) Is there sufficient evidence to refute the claim at the 2% level of signifigance?

b) What is the p-vaule?

c) What is the smallest value of alpha for which the claim will be rejected?

Solutions

Expert Solution

a. Here claim is that mean is atleast 64.

Now as we know null hypothesis is always with equality sign.

and so

As n>30, we will use z test statistics

The z-critical value for a left-tailed test, for a significance level of ?=0.02 is

zc?=?2.05

Graphically

As z statistics is not in the rejection region we fail to reject the null hypothesis.

Hence the claim is not rejected

b. P value is

c. As P value is 0.0384 so alpha value of 0.04 i.e. 4% will serve as to reject the claim.


Related Solutions

A random sample of 50 measurements resulted in a sample mean of 62 with a sample standard deviation 8. It is claimed that the true population mean is at least 64.
A random sample of 50 measurements resulted in a sample mean of 62 with a sample standard deviation 8. It is claimed that the true population mean is at least 64.(a) Is there sufficient evidence to refute the claim at the 2% level of significance?(b) What is the p-value?(c) What is the smallest value of α for which the claim will be rejected?
A simple random sample of 50 items from a population with σ = 8 resulted in a sample mean of 32.
  A simple random sample of 50 items from a population with σ = 8 resulted in a sample mean of 32. (Round your answers to two decimal places.) (a) Provide a 90% confidence interval for the population mean. to (b) Provide a 95% confidence interval for the population mean. to (c) Provide a 99% confidence interval for the population mean. to
A simple random sample of 50 items from a population with = 6 resulted in a...
A simple random sample of 50 items from a population with = 6 resulted in a sample mean of 39. If required, round your answers to two decimal places. a. Provide a 90% confidence interval for the population mean. to b. Provide a 95% confidence interval for the population mean. to c. Provide a 99% confidence interval for the population mean.
A simple random sample of 70 items resulted in a sample mean of 60. The population...
A simple random sample of 70 items resulted in a sample mean of 60. The population standard deviation is σ = 15. (a) Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.) _________ to _________ (b) Assume that the same sample mean was obtained from a sample of 140 items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.) _________ to _________ (c) What is the...
A simple random sample of 30 items resulted in a sample mean of25. The population...
A simple random sample of 30 items resulted in a sample mean of 25. The population standard deviation is 7 . Round your answers to two decimal places a. What is the standard error of the mean, ? b. At 95% confidence, what is the margin of error?
A simple random sample of 30 items resulted in a sample mean of 30. The population...
A simple random sample of 30 items resulted in a sample mean of 30. The population standard deviation is 15. a. Compute the 95% confidence interval for the population mean. Round your answers to one decimal place. ( ,  ) b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean. Round your answers to two decimal places. ( ,  )
A simple random sample of 60 items resulted in a sample mean of 80. The population...
A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is σ = 5. (a) Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.)   to   (b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.)   to  
A simple random sample of 60 items resulted in a sample mean of 80. The population...
A simple random sample of 60 items resulted in a sample mean of 80. The population standard deviation is σ = 5. (a) Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.)   to   (b) Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.)   to  
A simple random sample of 60 items resulted in a sample mean of 65. The population...
A simple random sample of 60 items resulted in a sample mean of 65. The population standard deviation is 16. a. Compute the 95% confidence interval for the population mean (to 1 decimal). ( , ) b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean (to 2 decimals). ( , ) c. What is the effect of a larger sample size on the margin of...
A simple random sample of 60 items resulted in a sample mean of 65. The population...
A simple random sample of 60 items resulted in a sample mean of 65. The population standard deviation is 16. a. Compute the 95% confidence interval for the population mean (to 1 decimal). ( , ) b. Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean (to 2 decimals). ( , ) c. What is the effect of a larger sample size on the margin of...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT