Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 11: Q. 40 (page 755)

Preventing strokes Refer to Exercise 38. Which treatment seems to be most effective? Least effective? Justify your choices.

Short Answer

Expert verified

The most effective treatment is both Aspirin and Dypiridamole and the least effective is Placebo.

Step by step solution

01

Given information

We need to find the most effective and least effective treatment to prevent stroke.

02

Explanation

We know that

Expected frequencies are a product of row and column total divided by table total. So,

ROW AND COLUMN NUMBER
EXPECTED FREQUENCY
E11
205.81
E12
1443.19
E21
205.81
E22
1443.19
E31
206.44
E32
1447.56
E41
205.94
E42
1444.06

The expected frequency of the number of successes deviates the most from the observed frequency, but the expected frequency for the treatment is higher than the observed frequency (expected 205.94and observed 157). As a result, the treatment of both is the most successful.

We see that for the treatment Placebo, the expected frequency of the number of successes differs the greatest from the observed frequency, whereas the expected frequency is lower than the observed frequency (expected 205.81and observed 250). As a result, the Placebo appears to be the least effective treatment.

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.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

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

Sorry, no chi-square How do U.S. residents who travel overseas for leisure differ from

those who travel for business? The following is the breakdown by occupation.

Occupation
Leisure travelers (%)
Business travelers (%)
Professional/technical
36
39
Manager/executive
23
48
Retired
14
3
Student
7
3
Other
20
7
Total
100
100

Explain why we can’t use a chi-square test to learn whether these two distributions differ

significantly.

All current-carrying wires produce electromagnetic (EM) radiation, including the electrical wiring running into, through, and out of our homes. High-frequency EM radiation is thought to be a cause of cancer. The lower frequencies associated with household current are generally assumed to be harmless. To investigate the relationship between current configuration and type of cancer, researchers visited the addresses of a random sample of children who had died of some form of cancer (leukemia, lymphoma, or some other type) and classified the wiring configuration outside the dwelling as either a high-current configuration (HCC) or a low-current configuration (LCC). Here are the data:

Computer software was used to analyze the data. The output included the value X2=0.435

Which of the following is the expected count of cases with lymphoma in homes with an HCC?

a. 79×31215

b. 10×21215

c. 79×3110

d. 136×31215

e. None of these

Roulette Refer to Exercise 2.

a. Confirm that the expected counts are large enough to use a chi-square distribution to calculate the P-value. What degrees of freedom should you use?

b. Use Table C to find the P-value. Then use your calculator’s χ2 cdf command.

c. What conclusion would you draw about whether or not the roulette wheel is operating correctly?

Stress and heart attacks You read a newspaper article that describes a study of whether stress management can help reduce heart attacks. The 107subjects all had reduced blood flow to the heart and so were at risk of a heart attack. They were assigned at random to three groups. The article goes on to say:

One group took a four-month stress management program, another underwent a four-month exercise program, and the third received usual heart care from their personal physicians. In the next three years, only 3of the 33people in the stress management group suffered "cardiac events," defined as a fatal or non-fatal heart attack or a surgical procedure such as a bypass or angioplasty. In the same period, 7of the 34people in the exercise group and 12out of the 40patients in usual care suffered such events.

a. Use the information in the news article to make a two-way table that describes the study results.

b. Compare the success rates of the three treatments in preventing cardiac events.

c. Do the data provide convincing evidence at the α=0.05level that the true success rates for patients like these are not the same for the three treatments?

A Type I error would occur if we found convincing evidence that

a. HCC wiring caused cancer when it actually didn’t.

b. HCC wiring didn’t cause cancer when it actually did.

c. there is no association between the type of wiring and the form of cancer when there actually is an association.

d. there is an association between the type of wiring and the form of cancer when there actually is no association.

e. the type of wiring and the form of cancer have a positive correlation when they actually don’t.
See all solutions

Recommended explanations on Math Textbooks

Mechanics Maths

Read Explanation

Applied Mathematics

Read Explanation

Statistics

Read Explanation

Discrete Mathematics

Read Explanation

Probability and Statistics

Read Explanation

Geometry

Read Explanation
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.

Sign-up for free