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Chapter 1: Problem 29

A study is designed to test the effect of light level on exam performance of students. The researcher believes that light levels might have different effects on males and females, so wants to make sure both are equally represented in each treatment. The treatments are fluorescent overhead lighting, yellow overhead lighting, no overhead lighting (only desk lamps). (a) What is the response variable? (b) What is the explanatory variable? What are its levels? (c) What is the blocking variable? What are its levels?

Short Answer

Expert verified
(a) Exam performance; (b) Light level (fluorescent, yellow, none); (c) Gender (male, female).

Step by step solution

01

Identify the Response Variable

To find the response variable, look for the main outcome that the study is trying to measure or explain. In this study, we are concerned with the performance of students on exams under different lighting conditions. Thus, the response variable is 'exam performance'.
02

Determine the Explanatory Variable

The explanatory variable is the one that is being manipulated or categorized to observe its effect on the response variable. Here, the type of lighting is being changed to see its impact on exam performance. Therefore, the explanatory variable is 'light level'.
03

Identify Levels of the Explanatory Variable

Levels refer to different conditions or categories of the explanatory variable. For light level, the levels are 'fluorescent overhead lighting', 'yellow overhead lighting', and 'no overhead lighting (only desk lamps)'.
04

Identify the Blocking Variable

A blocking variable is used to group similar experimental units together. In this scenario, gender is used to ensure that both males and females are equally represented in each type of light condition. Hence, the blocking variable is 'gender'.
05

Determine Levels of the Blocking Variable

Levels of a blocking variable are the categories within the blocking variable. Given that gender is the blocking variable, its levels are 'male' and 'female'.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Response Variable
The response variable in an experimental design is the main outcome that the researcher aims to measure or explain. In simple terms, it's the effect that might change when you tweak different aspects of the experiment. In the study about light levels and exam performance, the response variable is the students' exam performance under different lighting conditions. Researchers are interested in how well the students perform on exams when exposed to various light settings.
  • Measures the main effect or outcome
  • In this context, it's the scores achieved by students on exams
  • Helps to determine the success or impact of the experiment
Identifying the correct response variable is crucial as it indicates what the study is primarily investigating.
Explanatory Variable
Explanatory variables are those manipulated or changed to observe how they affect the response variable. They are the variables the researcher is interested in studying further to see if adjustments influence the outcome. In our case, the explanatory variable is the "light level."
  • Central to explaining changes in the response variable
  • Manipulated to understand its impact
  • Involves selecting different types of lighting conditions for analysis
The goal is to understand whether differing light levels lead to variations in exam performance.
Blocking Variable
Blocking variables are used in experimental design to reduce the effects of variability and to ensure that the experimental comparisons are fair. They help control for factors that could influence the results inadvertently. In this study, "gender" is identified as the blocking variable because it groups students in a way that ensures equal representation of both genders across all lighting conditions.
  • Helps to minimize confounding variables
  • Ensures fair representation and controls for variability
  • Aids in creating balanced experimental conditions
By using a blocking variable like gender, the study attempts to isolate the effect of light levels on exam performance unclouded by any gender-based differences.
Levels
Levels refer to the different categories or conditions of a variable. Both explanatory and blocking variables have levels, helping to identify the various groups under consideration. For the light level, we have three levels: "fluorescent overhead lighting," "yellow overhead lighting," and "no overhead lighting (only desk lamps)." Each level represents a unique lighting condition that students will be subjected to during the study.
  • Defines the specific conditions participants are exposed to
  • Helps clarify the structure of the experiment
  • Allows comparison across different scenarios
Similarly, gender as the blocking variable presents two levels: "male" and "female," ensuring equal representation and balanced testing conditions for each lighting scenario.

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Most popular questions from this chapter

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