/*! 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. T4.3 A study of treatments for angina... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 4: Q. T4.3 (page 289)

A study of treatments for angina (pain due to low blood supply to the heart) compared

bypass surgery, angioplasty, and use of drugs. The study looked at the medical records

of thousands of angina patients whose doctors had chosen one of these treatments. It

found that the average survival time of patients given drugs was the highest. What do

you conclude?

a. This study proves that drugs prolong life and should be the treatment of choice.

b. We can conclude that drugs prolong life because the study was a comparative

experiment.

c. We can鈥檛 conclude that drugs prolong life because the patients were volunteers.

d. We can鈥檛 conclude that drugs prolong life because the groups might differ in ways

besides the treatment.

e. We can鈥檛 conclude that drugs prolong life because no placebo was used.

Short Answer

Expert verified

The correct option is:

d. We can鈥檛 conclude that drugs prolong life because the groups might differ in ways besides the treatment.

Step by step solution

01

Given information

We have been given four options from which we have to select the correct one.

a. This study proves that drugs prolong life and should be the treatment of choice.

b. We can conclude that drugs prolong life because the study was a comparative

experiment.

c. We can鈥檛 conclude that drugs prolong life because the patients were volunteers.

d. We can鈥檛 conclude that drugs prolong life because the groups might differ in ways

besides the treatment.

e. We can鈥檛 conclude that drugs prolong life because no placebo was used

02

Explanation

An observational research attempts to collect data without disrupting the scene being observed.

As a result, we can deduce that the study in question makes use of records and is thus an observational study.

An observational study cannot conclude cause and effect (an experiment is required), because observational studies always involve the possibility of confounding variables (as some variables not included in the study could influence the results without us knowing it).

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

A recent random sample of n=805adult U.S. residents found that the proportion who rated the honesty and ethical standards of nurses as high or very high is 0.85. This is 0.15higher than the proportion recorded for doctors, the next highest-ranked profession.

a. Identify the sample and the population in this setting.

b. Do you think that the proportion of all U.S. residents who would rate the honesty and ethical standards of nurses as high or very high is exactly 0.85? Explain your answer.

c. What is the benefit of increasing the sample size in this context?

A maker of fabric for clothing is setting up a new line to 鈥渇inish鈥� the raw fabric. The line will use either metal rollers or natural-bristle rollers to raise the surface of the fabric; a dyeing-cycle time of either 30or40minutes; and a temperature of either 150掳Cor175掳C. Three specimens of fabric will be subjected to each treatment and scored for quality.

a. List the factors in this experiment and state how many levels each factor has.

b. If the researchers used every possible combination to form the treatments, how many

treatments were included in the experiment?

c. List two of the treatments.

Sampling mall shoppers You may have seen the mall interviewer, clipboard in hand, approaching people passing by. Explain why even a large sample of mall shoppers would not provide a trustworthy estimate of the current unemployment rate in the city where the mall is located.

A farmer is experimenting to determine which variety of apple trees, Fuji or Gala, will produce more fruit in his orchard. The orchard is divided into 20equally sized square plots. He has 10trees of each variety and randomly assigns each tree to a separate plot in the orchard. What is the experimental unit (s) in this study? a. The trees; b. The farmer; c. The plots d. The orchard e. The apples

In the experiment of the preceding exercise, the subjects were randomly assigned to the

different treatments. What is the most important reason for this random assignment?

a. Random assignment eliminates the effects of other variables such as stress and body

weight.

b. Random assignment is a good way to create groups of subjects that are roughly

equivalent at the beginning of the experiment.

c. Random assignment makes it possible to make a conclusion about all men.

d. Random assignment reduces the amount of variation in blood pressure.

e. Random assignment prevents the placebo effect from ruining the results of the study.
See all solutions

Recommended explanations on Math Textbooks

Applied Mathematics

Read Explanation

Mechanics Maths

Read Explanation

Discrete Mathematics

Read Explanation

Decision Maths

Read Explanation

Geometry

Read Explanation

Calculus

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.