For each of the following scenarios, identify which research strategy is used: descriptive, correlational, experimental, or nonexperimental. (Note: For now, do not differentiate between nonexperimental and quasi-experimental studies. The distinction between them is discussed in Chapter 10.)

a. Dr. Jones conducts a study examining the relationship between sugar consumption and activity level for 5-year-old children. Sugar consumption scores are obtained by interviewing each child’s parents and activity level is measured by observing the children during an outdoor play period.

b. Dr. Jones conducts a study examining the relationship between sugar consumption and activity level for 5-year-old children. Sugar consumption scores are obtained by interviewing each child’s parents. Based on the interview results, the boys are divided into two groups: those who consume large amounts of sugar and those who eat relatively small amounts. Then activity level is measured by observing the children during an outdoor play period to determine if there is any difference between the two groups.

c. Dr. Jones conducts a study examining the relationship between sugar consumption and activity level for 5-year-old children. A group of children is randomly separated into two groups. One group is given a sugary cereal for breakfast and the other is given oatmeal. Activity level is then measured by observing the children during an outdoor play period to determine if there is any difference between the two groups.

d. Dr. Jones conducts a study examining activity level of 5-year-old children. Each afternoon for 1 week, a group of boys in a child-care center is observed during a 30-minute period while they play outdoors. Activity level is recorded during the 30-minute period.