To select the best answer for each question.
Answer to Problem 5PT
(b) Random assignment will tend to average out all other controlled factors such as soil fertility so that they are not confounded with the treatment effects.
Explanation of Solution
Given Information:
Consider an experiment to investigate the effectiveness of different insecticides in controlling pests and their impact on the productivity of tomato plants. What is the best reason for randomly assigning treatment levels (spraying or not spraying) to the experimental units (farms)? (a) Random assignment allows researchers to generalize conclusions about the effectiveness of the insecticides to all farms. (b) Random assignment will tend to average out all other uncontrolled factors such as soil fertility so that they are not confounded with the treatment effects. (c) Random assignment eliminates the effects of other variables, like soil fertility. (d) Random assignment eliminates chance variation in the responses. (e) Random assignment helps avoid bias due to the placebo effect.
Random assignment means that you randomly assign those participants to either assignment. By randomly assigning treatments we are attempting to make the different groups look as similar as possible so that we can reduce the likelihood of a confounding variable.
Hence option (b) is correct.
Chapter 4 Solutions
The Practice of Statistics for AP - 4th Edition
Additional Math Textbook Solutions
Introductory Statistics (2nd Edition)
Introductory Statistics
Elementary Statistics
Essentials of Statistics (6th Edition)
Elementary Statistics: Picturing the World (6th Edition)
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman