/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 9.94 Class Project: Quality Assurance... [FREE SOLUTION] | 91影视

91影视

Class Project: Quality Assurance. This exercise can be don individually or, better yet, as a class project. For the pretzel-packagin hypothesis test in Example 9.1 on page 352, the null and alternativ hypotheses are, respectively,
H0:=454g (machine is working properly)
H0:454g (machine is not working properly).
where is the mean net weight of all bags of pretzels packaged. The net weights are normally distributed with a standard deviation of 7.8g.
a. Assuming that the null hypothesis is true, simulate 100 samples of 25 net weights each.
b. Suppose that the hypothesis test is performed at the 5%significance level. Of the 100 samples obtained in part (a), roughly how many would you expect to lead to rejection of the null hypothesis? Explain your answer.

c. Of the 100 samples obtained in part (a), determine the number that lead to rejection of the null hypothesis.
d. Compare your answers from parts (b) and (c), and comment on any observed difference.

Short Answer

Expert verified

Part (a). We simulate 100 samples of size in the columns, C1 to C100.

Part (b). For 100 samples,the expected number of samples are rejected, is 0.05

Part (c). The number of samples that lead to reject the null hypothesis is 3 .

Part (d). The expected value of the number of samples that lead to reject the null hypothesis is greater as compared to the observed value.

Step by step solution

01

Part (a) Step 1. Given information

It is given that the null and alternative hypotheses are stated as follows:
H0:=454g(Machine is working properly.)
Versus
H0:454g (Machine is not working properly)
Here the mean net weight of all bags of pretzels package is given as .
Also it is given that the net weights are normally distributed with a standard deviation of7.8g.
That means =7.8g

02

Part (a) Step 2. Assuming that the null hypothesis is true, simulate 100 samples of 25 net weights each. 

Using MINITAB, we simulate 100 samples of 25 net weights each by assumingH0is true as follows:
Step 1: CalcRandom dataNormal
Step 2: enter the given data as follows:
Step 3: Click OK.
From the above three steps, we simulate 100 samples of size in the columns, C1 to C100.

03

Part (b) Step 1. Given information

It is given that the null and alternative hypotheses are stated as follows:
H0:=454g(Machine is working properly.)
Versus
H0:454g(Machine is not working properly)
Here the mean net weight of all bags of pretzels package is given as .
Also it is given that the net weights are normally distributed with a standard deviation of7.8g.
That means =7.8g

04

Part (b) Step 2. Suppose that the hypothesis test is performed at the 5%significance level. Of the 100 samples obtained in part (a), roughly how many would you expect to lead to rejection of the null hypothesis? Explain your answer. 

Here we have informed that the hypothesis test is performed at5% significance level. That means, we have
Thus, the probability of rejecting the null hypothesis is0.05. That means,
Therefore for 100 samples,the expected number of samples are rejected, is0.05

05

Part (c) Step 1. Given information

It is given that the null and alternative hypotheses are stated as follows:
H0:=454g(Machine is working properly.)
Versus
H0:454g(Machine is not working properly)
Here the mean net weight of all bags of pretzels package is given as.
Also it is given that the net weights are normally distributed with a standard deviation of7.8g.
That means =7.8g

06

Part (c) Step 2. Of the 100 samples obtained in part (a), determine the number that lead to rejection of the null hypothesis. 

Using MINITAB, we obtain the95% confidence interval for the 100 samples simulated in part
(a), as follows:
1 Store the data in a column named Cadmium level.
2 Choose Stat ? Basic Statistics ?1-Sample Z. .
3 Select the Samples in columns option button.
4 Click in the Samples in columns text box and specify C1-C2.
5 Click in the Standard deviation text box and type 78
6 Click the Options ... button.
7 Type 95 in the Confidence level text box.
8 Click the arrow button at the right of the Alternative drop-down list box and select greater than.
9 Click OK twice.

As per the requirement, we observe the number of samples for which the 95%confidence interval does not contain the value of mean

Therefore, we obtained the number of samples that lead to reject the null hypothesis is 3 .
07

Part (d) Step 1. Given information

It is given that the null and alternative hypotheses are stated as follows:
H0:=454g(Machine is working properly.)
Versus
role="math" localid="1651256756555" H0:454g(Machine is not working properly)
Here the mean net weight of all bags of pretzels package is given as .
Also it is given that the net weights are normally distributed with a standard deviation of7.8g.
That means =7.8g

08

Part (d) Step 2. Compare your answers from parts (b) and (c), and comment on any observed difference. 

From the parts (b) and (c), we observe that the expected value of the number of samples that lead to reject the null hypothesis is greater as compared to the observed value.
Therefore, we fail to reject the null hypothesis and hence we conclude that the machine is working properly.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Test Statistics. In Exercises 13鈥16, refer to the exercise identified and find the value of the test statistic. (Refer to Table 8-2 on page 362 to select the correct expression for evaluating the test statistic.)

Exercise 7 鈥淧ulse Rates鈥

Identifying H0and H1. In Exercises 5鈥8, do the following:

a. Express the original claim in symbolic form.

b. Identify the null and alternative hypotheses.

Pulse Rates Claim: The standard deviation of pulse rates of adult males is more than 11 bpm. For the random sample of 153 adult males in Data Set 1 鈥淏ody Data鈥 in Appendix B, the pulse rates have a standard deviation of 11.3 bpm.

Testing Claims About Proportions. In Exercises 9鈥32, test the given claim. Identify the null hypothesis, alternative hypothesis, test statistic, P-value, or critical value(s), then state the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. Use the P-value method unless your instructor specifies otherwise. Use the normal distribution as an approximation to the binomial distribution, as described in Part 1 of this section.

M&Ms Data Set 27 鈥淢&M Weights鈥 in Appendix B lists data from 100 M&Ms, and 27% of them are blue. The Mars candy company claims that the percentage of blue M&Ms is equal to 24%. Use a 0.05 significance level to test that claim. Should the Mars company take corrective action?

Vitamin C and Aspirin A bottle contains a label stating that it contains Spring Valley pills with 500 mg of vitamin C, and another bottle contains a label stating that it contains Bayer pills with 325 mg of aspirin. When testing claims about the mean contents of the pills, which would have more serious implications: rejection of the Spring Valley vitamin C claim or rejection of the Bayer aspirin claim? Is it wise to use the same significance level for hypothesis tests about the mean amount of vitamin C and the mean amount of aspirin?

Critical Values. In Exercises 21鈥24, refer to the information in the given exercise and do the following.

a. Find the critical value(s).

b. Using a significance level of = 0.05, should we reject H0or should we fail to reject H0?

Exercise 19

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.