Chapter 1.3, Problem 6MI

Summary Introduction

To identify:

The experimental group, control group. Independent variable and dependent variable in the given experiment.

Introduction:

Science is a body of knowledge based on study of nature. Biologists follow specificsteps to do research and answer queries. Scientists gather information from various experiments. Controlled experiments involve a control group and an experimental group.

Answer to Problem 6MI

Experimental group: The dogs that get new kind of food

Control group: The dogs that do not get new kind of food

Independent variable:The new kind of food

Dependent variable: Weight gain

Explanation of Solution

Experimental group − Controlled experiments involve a control group and an experimental group. Experimental group includes a group that is exposed to the factor being tested. In the given experiment, a group of dogs is fed on a new kind of food. So this group of dogs becomes the experimental group.

Control group - It includes a group that is used for comparison without the factor. By comparing the results of the control and experimental groups the biologists draw conclusions about the effect of the variable. In the given experiment, a group of dogs is fed on a new kind of food and its effect in terms of weight gain is compared with a group of dogs that are not fed on new food. So this group of dogs that are not fed on new food becomes the control group.

Independent variable - In a controlled experiment, only one condition is changed at a time. The condition that is tested is called the independent variable because it is the only change that affects the result of the experiment. In this case, introduction of new food is the factor that is changed. So it is the independent variable.

Dependent variable - While testing the independent variable, scientists observed a second condition that resulted due to change in independent variable.The condition caused by the change in independent variable is called dependent variable. Here, the weight of dogs changed due to introduction of new kind of food; so weight gain is the dependent variable.