Question

In each case below, we describe a study to determine whether exercise helps increase certain mood enhancing chemicals in the brain. Indicate whether each describes an experiment or an observational study.

a). Using a random sample of 100 people, we randomly assign half of them to participate in a regular exercise program for a six-week period while the other half makes no changes. At the end of the time period, we measure the brain chemicals.
b). We contact a random sample of 100 people and record how much each person exercises and also measure the chemicals in the brain for each person.

Answer 1

a) Experiment; b) Observational study

Step-by-step explanation:

a). This study describes an experiment. The researchers randomly assigned participants into two groups: one group that participated in a regular exercise program and another group that made no changes. By manipulating the independent variable (exercise) and measuring the brain chemicals at the end of the study, the researchers can determine if exercise increases certain mood enhancing chemicals in the brain.

b). This study describes an observational study. The researchers are observing and recording how much each person exercises and also measuring the brain chemicals in the brain for each person. They are not assigning the participants to specific groups or manipulating the independent variable.

Answer 2

A)Experimental Study

B)Observational Study

Step-by-step explanation:

Observational Study : A study where researchers simply collect data based on what is seen and heard and infer based on the data collected.

Experimental Study: A study which involve the random assignment of -participants into different groups in order to determine the causal effect of a certain condition on a certain outcome .

A) In this case we are randomly classifying the subjects into two groups, where one group participate in a regular exercise program for a six week period, while the other half makes no changes. In this Part we are not observing the data . we are doing experiment over here and comparing those two different groups.

So, By definition It is an experimental study

B) In this case we are recording the data of each person and decision will be based on data

So, By definition It is an observational study