Question

Q-7 Refer to Previous Exercise. (a) Based on this initial experience, determine the control limits for the range. Plot the experience on a chart. (b) Does there seem to be a time when there is too much variation in the temperature?

Q-8 A bicycle manufacturer randomly selects 10 frames each day and tests for defects. The number of defective frames found over the last 14 days is 3, 2, 1, 3, 2, 2, 8, 2, 0, 3, 5, 2, 0, 4. Construct a control chart for this process and comment on whether the process is “in control.”

Q-9 Scott Paper tests its toilet paper by subjecting 15 rolls to a wet stress test to see whether and how often the paper tears during the test. Following are the number of defectives found over the last 15 days: 2, 3, 1, 2, 2, 1, 3, 2, 2, 1, 2, 2, 1, 0, and 0. Construct a control chart for the process and comment on whether the process is “in control.”

Answer 1

For problem 1:

We have given the data for defective bicycle frame for 14 days like 3,2,1,3,2,2,8,2,0,3,5,2,0,4

Now take the mean of above given data

Mean=total sum/number of sum

Now derive the standard deviation for given data

Now mean of data is the control line value

Now find out the up control line and lower control line

Up control line=mean+(3*std deviation)

Lower control line=mean-(3* std deviation

For the bicycle frame problem no any consecutive point exception 5 and 6 on the same side of the control line so we can say that process is under control

For Scott paper test problem point 7,8 and 9 are on the same side of control line farther than (1*std deviation) from control line so the processes is not in control