/*! 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 R4.11. How long did I work? A psycholog... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 4: Q R4.11. (page 273)

How long did I work? A psychologist wants to know if the difficulty of a task influences our estimate of how long we spend working at it. She designs two sets of mazes that subjects can work through on a computer. One set has easy mazes and the other has hard mazes. Subjects work until told to stop (after 6 minutes, but subjects do not know this). They are then asked to estimate how long they worked. The psychologist has 30 students available to serve as subjects.

(a) Describe an experiment using a completely randomized design to learn the effect of difficulty on estimated time.

(b) Describe a matched pairs experimental design using the same 30 subjects.

(c) Which design would be more likely to detect a difference in the effects of the treatments?

Explain.

Short Answer

Expert verified

Part (a) It is necessary to compare two therapeutic groups.

Part (b) Now shuffle all of the slips and assign them to the pupils to choose from. Compare their times now.

Part (c) since it is in charge of regulating the disparities between the 30 subjects

Step by step solution

01

Part (a) Step 1: Given information

Number of students are 30

02

Part (a) Step 2: Concept

The random assignment method assigns subjects to treatments based on chance. Before the treatments are applied, random assignment establishes treatment groups that are comparable (except for chance variance). In experiments, randomization and comparison combined prevent bias or systematic favoritism.

03

Part (a) Step 3: Explanation

There are 30 pupils in total.

There are two types of maze treatments: easy and challenging.

Assign a number between one and thirty pupils. Give 15 pupils an easy maze and the remaining 15 students tougher mazes. The results of the two therapy groups should then be compared.

04

Part (b) Step 1: Explanation

Make 15 slips and write a simple maze on each one. Similarly, make 15 more slips and write a difficult maze on them. Now shuffle all of the slips and assign them to the pupils to choose from. Compare their times now.

05

Part (c) Step 1: Explanation

Because it is controlling the differences among the 30 participants, the matched pair is likely to detect the difference.

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

Room temperature and dexterity An expert on worker performance is interested in the effect of room temperature on the performance of tasks requiring manual dexterity. She chooses temperatures of 70掳Fand 90掳Fas treatments. The response variable is the number of correct insertions, during a 30-minute period, in a peg-and-hole apparatus that requires the use of both hands simultaneously. Each

subject is trained on the apparatus and then asked to make as many insertions as possible in 30 minutes of continuous effort.

(a) Outline a completely randomized design to compare dexterity at70掳 and 90掳. Twenty subjects are available.

(b) Because individuals differ greatly in dexterity, the wide variation in individual scores may hide the systematic effect of temperature unless there are many subjects in each group. Describe in detail the design of a matched pairs experiment in which

Sampling stuffed envelopes A large retailer prepares its customers鈥� monthly credit card bills using an automatic machine that folds the bills, stuffs them

into envelopes, and seals the envelopes for mailing. Are the envelopes completely sealed? Inspectors choose 40 envelopes from 1000 stuffed each hour for visual inspection. Identify the population and the sample.

Aw, rats! A nutrition experimenter intends to compare the weight gain of newly weaned male rats fed Diet A with that of rats fed Diet B. To do this, she will feed each diet to 10 rats. She has available 10rats from one litter and 10rats from a second litter. Rats in the first litter appear to be slightly healthier.

(a) If the 10rats from Litter 1 were fed Diet A, the effects of genetics and diet would be confounded, and the experiment would be biased in favor of Diet A. Explain this statement carefully.

(b) Describe a better design for this experiment.

Pain relief study Fizz Laboratories, a pharmaceutical company, has developed a new drug for relieving chronic pain. Sixty patients suffering from arthritis and needing pain relief are available. Each patient will be treated and asked an hour later, 鈥淎bout what percent of pain relief did you experience?鈥�

(a) Why should Fizz not simply administer the new drug and record the patients鈥� responses?

(b) Should the patients be told whether they are getting the new drug or a placebo? How would this knowledge probably affect their reactions?

Acupuncture and pregnancy A study sought to determine whether the ancient Chinese art of acupuncture could help infertile women become pregnant.41 One hundred sixty healthy women undergoing treatment with artificial insemination were recruited for the study. Half of the subjects were randomly assigned to receive acupuncture treatment 25minutes before embryo transfer and again 25

minutes after the transfer. The remaining 80subjects were instructed to lie still for 25minutes after the embryo transfer.

Results: In the acupuncture group, 34women became pregnant. In the control group, 21women became pregnant.

(a) Describe how the three principles of experimental design were addressed in this study.

(b) The difference in the percent of women who became pregnant in the two groups is statistically significant. Explain what this means to someone who

knows little statistics.

(c) Explain why the placebo effect prevents us from concluding that acupuncture caused the difference in pregnancy rates.
See all solutions

Recommended explanations on Math Textbooks

Applied Mathematics

Read Explanation

Statistics

Read Explanation

Geometry

Read Explanation

Theoretical and Mathematical Physics

Read Explanation

Mechanics Maths

Read Explanation

Discrete Mathematics

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.