Question

In: Operations Management

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He...

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each:

Day Weight (ounces)
Monday 23 22 23 24
Tuesday 23 21 19 21
Wednesday 20 19 20 21
Thursday 18 19 20 19
Friday 18 20 22 20

23 What is the sample mean package weight for Thursday?

Multiple Choice

  • 19 ounces

  • 20 ounces

  • 20.6 ounces

  • 21 ounces

  • 23 ounces

24 What is the mean of the sampling distribution of sample means when this process is in control?

Multiple Choice

  • 18 ounces

  • 19 ounces

  • 20 ounces

  • 21 ounces

  • 22 ounces

25 If he uses upper and lower control limits of 22 and 18 ounces, on what day(s), if any, does this process appear to be out of control?

Multiple Choice

  • Monday

  • Tuesday

  • Monday and Tuesday

  • Monday, Tuesday, and Thursday

  • None

Solutions

Expert Solution

Answer 23 –

Sample mean package weight for Thursday = (Weight of Package 1 + Weight of Package 2 + Weight of Package 3 + Weight of Package 4) / Number of packages

= (18+19+20+19)/4

= 19 ounces

Answer 24 –

Sample means for all days using formula mentioned above–

Monday = (23+22+23+24)/4 = 23

Tuesday = (23+21+19+21)/4 = 21     

Wednesday = (20+19+20+21)/4 = 20

Thursday = (18+19+20+19)/4 = 19

Friday = (18+20+22+20)/4 = 20

Mean of the sampling distribution of sample means = Sum of sample means of all days / Number of days

= (23+21+20+19+20)/5

= 20.6 = 21 ounces (rounded off)

Answer 25 – Monday

Explanation:

Upper Control Limit = 22

Lower Control Limit = 18

Sample means of Tuesday, Wednesday, Thursday and Friday falls under these limits. However, sample mean of Monday is 23 which does not fall under these limits. Therefore, on Monday process appears to be out of control.

keosha answered 3 months ago
Next > < Previous

Related Solutions

A quality analyst wants to construct a sample mean chart for controlling a packaging process. Each...
A quality analyst wants to construct a sample mean chart for controlling a packaging process. Each day last week, he randomly selected six packages and weighed each. The data from that activity appears below.                   Weight (in grams) Day Package 1 Package 2 Package 3 Package 4 Package 5 Package 6 Monday 23 22 23 24 23 21 Tuesday 23 21 19 21 24 20 Wednesday 20 19 20 21 19 20 Thursday 18 19 20 19 21 22 Friday...
Q6. A quality analyst took the following samples as a pilot study to construct the mean...
Q6. A quality analyst took the following samples as a pilot study to construct the mean and range charts. The data below shows the weight in ounces. Construct the mean and range charts showing all control (action) –upper and lower limits, and warning upper and lower limits. Sample Number Item1 Item2 Item3 Item4 Sample 1 11.9 12.5 12.4 12.7 Sample 2 12.5 12.5 12.4 12.8 Sample 3 12.2 12.8 12.7 12 Sample 4 12.3 12.4 12.8 12.4 Sample 5 12.1...
For following data: a. Construct an R-chart for this process. b. Construct an X-bar chart for...
For following data: a. Construct an R-chart for this process. b. Construct an X-bar chart for this process. c. Does the process appear to be in control? Why or why not? ​ d. Why must the R chart be read before the x-chart? Hour Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 1 98.2706 98.82376 101.8175 100.1819 102.9594 101.165 95.25957 98.97423 2 100.7166 101.8866 98.56813 98.77126 101.8273 98.20298 101.6975 99.63706 3 98.9922...
Bird’s data analyst wants to model the sample mean and sample variance of net revenue of...
Bird’s data analyst wants to model the sample mean and sample variance of net revenue of scooters. They plan to take a random sample of 25 of its scooters in Austin. They will record weekly net revenue brought in by each scooter. They decide it is reasonable to assume that weekly revenue of scooters is approximately normally distributed with a standard deviation of $50 (variance of 2,500 squared dollars). Find values a and b such that (i) the probability is...
A quality inspector is worrying about the defective produced in the production process. He wants to...
A quality inspector is worrying about the defective produced in the production process. He wants to test that the average defectives produced are 145 or less. He collects a sample of 25 production runs and found that a sample mean of 150 defectives were produced with a std deviation of 20. With this information he wishes to perform a hypothesis test at 5% significance level. The decision is to: Reject Null; test statistic < critical value (or t test statistic...
Bird’s data analyst wants to model the sample mean distance of scooter rides. They plan to...
Bird’s data analyst wants to model the sample mean distance of scooter rides. They plan to take a random sample of 41 scooter rides and to record the distance traveled on each ride (distance before the rider “releases” the scooter and the charge is processed). They decide it is reasonable to assume that the distribution of distances is approximately normal, but they don’t know the variance of the distribution. In the sample, the mean is 0.54 mile and the standard...
Use the following to answer questions 14-19: A design engineer wants to construct a sample mean...
Use the following to answer questions 14-19: A design engineer wants to construct a sample mean chart and a range chart for controlling the diameter for a component used in surgeries. The following table contains measurements (in millimeters) of the diameter for a component. Four samples of five units each were taken at random two-hour intervals. Observation number Sample 1 2 3 4 5 1 8 9 10 9 8 2 9 7 9 9 8 3 8 9 9...
A quality manager asked his team to implement p control chart for a process that was...
A quality manager asked his team to implement p control chart for a process that was recently introduced. The team collected samples of size n = 100 parts hourly over a period of 30 hours and determined the proportion of nonconforming parts for each sample. The mean proportion of nonconforming parts for 30 samples turned out to be 0.025. Determine the upper and lower control limits for the p chart. Discuss how you will use the p Chart and what...
A quality analyst at Paintfast Manufacturing Co. wants to determine if a new paint formulation, used...
A quality analyst at Paintfast Manufacturing Co. wants to determine if a new paint formulation, used to paint parts for a customer’s assembly oper- ation will dry fast enough to meet the customer’s needs. The customer would prefer to obtain a high level of “dryability” at low temperatures, even if it requires a higher level of drying agent. He hypothesizes that a high level of drying agent will result in high dryability, high temperature— alone—will result in a moderately high...
A sales analyst wants to determine whether there is difference in the mean monthly sales (in...
A sales analyst wants to determine whether there is difference in the mean monthly sales (in RM) of cosmetic company of six sales region in Johor. Several salespersons from each region are chosen and their monthly sales were recorded in Table Q2. Monthly sale (RM) Company A Company B Company C Company D Company E Company F 4250 3930 3960 4350 4150 3970 3980 4010 4020 4450 3890 4160 4020 4050 4130 3880 4568 4370 4130 4220 4350 4574 4480...
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT