State the conclusion based on the results of the test. The standard deviation in the pressure required to open a certain valve is known to be a 0.6 psi. Due to changes in the manufacturing process, the quality-control manager feels that the pressure variability has been reduced. The null hypothesis was rejected. Choose the correct answer below. OA. The standard deviation in the pressure has been reduced. OB. There is not sufficient evidence that the standard deviation in the pressure required to open a certain valve has not changed. OC. There is sufficient evidence that the standard deviation in the pressure required to open a certain vaive has been reduced. OD. The standard deviation in the pressure has not changed. OE. There is not sufficient evidence that the standard deviation in the pressure required to open a certain valve has been reduced OF. There is sufficient evidence that the standard deviation in the pressure required to open a certain valve has not changed. Click to select your answer and then click Check Answer. All parts showing Clear All Question Help Question Viewer