Question

State the conclusion based on the results of the test. The standard deviation standard deviation in in the pressure required to open a certain valve is known to be sigma equals 1.1 psi. σ=1.1 psi. Due to changes in the manufacturing​ process, the​ quality-control manager feels that the pressure pressure variability variability has changed changed. The null hypothesis was not rejected not rejected. Choose the correct answer below. A. There is is sufficient evidence that the standard deviation standard deviation in in the pressure required to open a certain valve has changed changed. B. There is is sufficient evidence that the standard deviation standard deviation in in the pressure required to open a certain valve has not changed. C. The standard deviation standard deviation in in the pressure has not changed. D. There is not is not sufficient evidence that the standard deviation standard deviation in in the pressure required to open a certain valve has not changed. E. There is not is not sufficient evidence that the standard deviation standard deviation in in the pressure required to open a certain valve has changed changed. F. The standard deviation standard deviation in in the pressure has changed changed.

Answer 1

B

Explanation:

Null hypothesis is not rejected if the test statistics show that the difference between observed and expected value is not significant and any difference is only due to chance.

So there is sufficient evidence from statistics that null hypothesis is true and the standard deviation in the pressure required to open a certain valve has not changed.

since evidence has to be there when null hypothesis is tested, optionC, D and E are rejected.

There is no change in standard deviation so option A and F are rejected.