/*! 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.24 Acupuncture and pregnancy A stud... [FREE SOLUTION] | 91影视

91影视

Acupuncture and pregnancy A study reported in the medical journal Fertility and Sterility sought to determine whether the ancient Chinese art of acupuncture could help infertile women become pregnant. One hundred sixty healthy women who planned to have IVF were recruited for the study. Half of the subjects 80were randomly assigned to receive acupuncture 25minutes before embryo transfer and again 25minutes after the transfer. The remaining 80women were assigned to a control group and instructed to lie still for 25minutes after the embryo transfer. Results are shown in the table below.


Acupuncture
Control group
Pregnant3421
Not pregnant4659
Total8080

Is the pregnancy rate significantly higher for women who received acupuncture? To find out, researchers perform a test of H0:P1=P2versus H;P1>P2, whereP1&P2are the actual pregnancy rates for women like those in the study who do and don't receive acupuncture, respectively.

(a) Name the appropriate test and check that the conditions for carrying out this test are met.

(b) The appropriate test from part (a) yields a P-value of 0.0152Interpret thisP-value in context.

(c) What conclusion should researchers draw at the =0.05significance level? Explain.

(d) What flaw in the design of the experiment prevents us from drawing a cause-and-effect conclusion? Explain.

Short Answer

Expert verified

(a) Two sample ztest can be use.

(b) The p value of 0.0152indicates that there is a 1.52percent chance that there will be no difference in pregnancy rates between the treatment and control groups.

(c) Pregnancies are more common among women who receive acupuncture than among women who do not.

(d) The women in the control group were aware that they had not had acupuncture since they could see it being done to them. This may have an impact on their behaviour, influencing whether or not they become pregnant. This is when the experiment fails.

Step by step solution

01

Part (a) Step 1: Given Information

Given in the question that

The number of women in the treatment group who became pregnant was=34

In the control group, the number of women who became pregnant was lower.=21

total number of women in treatment group=80

In the control group, there were a total of 80women.

P1s the percentage of women in the treatment group who became pregnant.be the proportion of women who became pregnant in the control group P2

The null and alternative hypothesis are

H0:P1=P2

H:P1>P2

We have to name the appropriate test and check that the conditions for carrying out this test are met.

02

Part (a) Step 2: Explanation

To execute a two-sample z test for proportional differences, the following conditions must be met.

1. The sample should be random

2.np>10

3.n1-p>10

4.The observation should be independent.

P1=3480=0.43

P2=2180=0.26

n1p1=80*0.43=34n1p1>10n11-p1=80*(1-0.34)=46n11-p1>10

n2p2=80*0.26=21n2p2>10n21-p2=80*(1-0.26)=59n21-p2>10

The women's groups are treated as independent because the experiment is randomized. If one woman becomes pregnant, no information about another woman is revealed. As a result, each group's individual observations are likewise deemed independent.

Therefore two sampleztest can be use.

03

Part (a) Step 1: Given Information 

Given in the question that the p value is0.0152we have to interpret p value of the significance test.

04

Part (b) Step 2: Explanation  

The p value is the probability that the null hypothesis is correct. The p value of 0.0152 indicates that there is a 1.52percent chance that there will be no difference in pregnancy rates between the treatment and control groups.

05

Part (c)  Step 1: Given Information  

Given in the question that the value of p is 0.0152and the significance level is=0.05. we have to know the conclusion drawn n significance test at 5% level of significance.

06

Part (c) Step 2: Explanation  

The p value of 0.0152is less than the 0.05level of significance. The null hypothesis is rejected at the level of significance of 5percent. The proportion of pregnancies in the treatment group is higher than in the control group, we conclude. As a result, the proportion of pregnancies among women who receive acupuncture is higher than among women who do not.

07

Part (d)  Step 1: Given Information  

We have to find out that at what flaw in the design of the experiment prevents us from drawing a cause-and-effect conclusion.

08

Part (d) Step 2: Explanation  

The women in the control group were aware that they had not had acupuncture since they could see it being done to them. This may have an impact on their behaviour, influencing whether or not they become pregnant. This is when the experiment fails.

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

School Ahas 400students and School Bhas 2700students. A local newspaper wants to compare the distributions of SAT scores for the two schools. Which of he following would be the most useful for making this comparison?

(a) Back-to-back stemplots for A and B

(b) A scatterplot of A versus B

(c) Dotplots for A and B drawn on the same scale

(d) Two relative frequency histograms of A and B drawn on the same scale

(e) Two frequency histograms for A and B drawn on the same scale

Shortly before the2008 presidential election, a survey was taken by the school newspaper at a very large state university. Randomly selected students were asked, 鈥淲hom do you plan to vote for in the upcoming presidential election?鈥 Here is a two-way table of the responses by political persuasion for 1850students:

Which of the following statements about these data is true?

(a) The percent of Republicans among the respondents is 41%.

(b) The marginal distribution of the variable choice of candidate is given by Obama: 55.6%; McCain: 37.6%; Other:1.1%; Undecided: 5.7%.

(c) About 11.2%of Democrats reported that they planned to vote for McCain.

(d) About 44.6%of those who are undecided are Independents.

(e) The conditional distribution of political persuasion among those for whom McCain is the candidate of choice is Democrat: 7.5%; Republican: 84.0%; Independent 18.8%:

41. Literacy rates Do males have higher average literacy rates than females in Islamic countries? The table below shows the percent of men and women at least 15years old who were literate in 2008in the major Islamic nations. (We omitted countries with populations of less than3million.) Data for a few nations, such as Afghanistan and Iraq, were not available.

How quickly do synthetic fabrics such as polyester decay in landfills? A researcher buried polyester strips in the soil for different lengths of time, then dug up the strips and measured the force required to break them. Breaking strength is easy to measure and is a good indicator of decay. Lower strength means the fabric has decayed. For one part of the study, the researcher buried 10strips of polyester fabric in well-drained soil in the summer. The strips were randomly assigned to two groups: 5of them were buried for 2weeks and the other 5were buried for 16weeks. Here are the breaking strengths in pounds

Do the data give good evidence that polyester decays more in 16weeks than in 2weeks? Carry out an appropriate test to help answer this question .

Expensive ads Consumers who think a product鈥檚 advertising is expensive often also think the product must be of high quality. Can other information undermine this effect? To find out, marketing researchers did an experiment. The subjects were 90 women from the clerical and administrative staff of a large organization. All subjects read an ad that described a fictional line of food products called 鈥淔ive Chiefs.鈥 The ad also described the major TV commercials that would soon be shown, an unusual expense for this type of product. The 45women who were randomly assigned to the control group read nothing else. The 45in the 鈥渦ndermine group鈥 also read a news story headlined 鈥淣o Link between Advertising Spending and New Product Quality.鈥 All the subjects then rated the quality of Five Chefs products on a seven-point scale. The study report said, 鈥淭he mean quality ratings were significantly lower in the undermine treatment (xA  4.56) than in the control treatment xC=5.05;t=2.64,P<0.01.

(a). Explain why the Random and Independent conditions are met in this case.

(b) The distribution of individual responses is not Normal, because there is only a seven-point scale. Why is it still proper to use a two-sample t-test?

(c) Interpret the P-value in context.

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.