Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 4: Q. 62 (page 264)

Side effects Even if an experiment is double-blind, the blinding might be compromised if side effects of the treatments differ. For example, suppose researchers at a skin-care company are comparing their new acne treatment against that of the leading competitor. Fifty subjects are assigned at random to each treatment, and the company’s researchers will rate the improvement for each of the 100subjects. The researchers aren’t told which subjects received which treatments, but they know that their new acne treatment causes a slight reddening of the skin. How might this knowledge compromise the blinding? Explain why this is an important consideration in the experiment.

Short Answer

Expert verified

The lack of blinding may bias the reported results because the results may be influenced by the placebo effect.

Step by step solution

01

Given information

We need to find how might this knowledge compromise the blinding and why this is an important consideration in the experiment.

02

Simplify

In a double-blind experiment, neither the subjects nor the people who measure them know which treatment they had, whereas in a single-blind experiment, either the people who measure or the people who get the results know which treatment they got (but not both).
The personnel who measure the treatment results will understand which treatment the participants received (due to skin reddening or not), and it may impact how they measure the results since they want the new drug to work, thus they may (perhaps subconsciously) modify the data considerably.

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

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’t conclude that drugs prolong life because the patients were volunteers.

d. We can’t conclude that drugs prolong life because the groups might differ in ways

besides the treatment.

e. We can’t conclude that drugs prolong life because no placebo was used.

Can a vegetarian or low-salt diet reduce blood pressure? Men with high blood pressure are

assigned at random to one of four diets: (1) normal diet with unrestricted salt; (2)

vegetarian with unrestricted salt; (3) normal with restricted salt; and (4) vegetarian with

restricted salt. This experiment has

  1. one factor, the type of diet.
  2. two factors, high blood pressure and type of diet.
  3. two factors, normal/vegetarian diet and unrestricted/restricted salt.
  4. three factors, men, high blood pressure, and type of diet.
  5. four factors, the four diets being compared.

Far from home? A researcher wants to estimate the average distance that students at a large community college live from campus. To find out, she surveys a simple random sample of students from the registrar’s database.

a. Will the researcher’s sample result be exactly the same as the true population's mean? Explain your answer.

b. Which would be more likely to produce a sample result closer to the true population value: an SRS of 100students or an SRS of 50students? Explain your answer.

Precise offers People often use round prices as first offers in a negotiation. But would a more precise number suggest that the offer was more reasoned and informed? In an experiment, 238adults played the role of a person selling a used car. Each adult received one of three initial offers: \(2000, \)1865(a precise under-offer), and \(2135(a precise over-offer). After hearing the initial offer, each subject made a counter-offer. The difference in the initial offer and counter-offer was the largest in the group that received the \)2000 offer. Describe how the researchers could have randomly assigned the subjects to the treatments

a. using slips of paper.

b. using technology.

c. using Table D.

Corn variety 1yielded 140bushels per acre last year at a research farm. This year, corn

variety 2, planted in the same location, yielded only 110bushels per acre. Based on these

results, is it reasonable to conclude that corn variety 1is more productive than corn variety

2?

a. Yes, because 140bushels per acre is greater than 110bushels per acre.

b. Yes, because the study was done at a research farm.

c. No, because there may be other differences between the two years besides the corn

variety.

d. No, because there was no use of a placebo in the experiment.

e. No, because the experiment wasn’t double-blind.
See all solutions

Recommended explanations on Math Textbooks

Probability and Statistics

Read Explanation

Decision Maths

Read Explanation

Geometry

Read Explanation

Applied Mathematics

Read Explanation

Discrete Mathematics

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.

Sign-up for free