Question

Color words $(4.2)$Let’s review the design of the study.

(a) Explain why this was an experiment and not an observational study.

(b) Did Mr. Starnes use a completely randomized design or a randomized block design? Why do you think he chose this experimental design?

(c) Explain the purpose of the random assignment in the context of the study. The data from Mr. Starnes’s experiment are shown below. For each subject, the time to perform the two tasks is given to the nearest second.

Short answer

a). An experiment and not an observational study because each subject had two treatments and they affect the individuals in the study.

b). Mr. Starnes uses a randomized block design.

c). The experience would be a possible confounding variable when no random assignment occurs.

Step-by-step solution

Part (a) Step 1: Given Information

Part (a) Step 2: Explanation

Mr. Starnes devised a study to investigate if the color in which words are printed affects your ability to read them, and whether the words themselves impact your ability to name the color in which they are printed. As we all know, an experiment involves purposely inflicting a treatment on individuals in order to study their reactions. And the observational research seeks to collect data without interfering with the situation they're seeing. As a result, this was an experiment rather than an observational study because each subject received two treatments, each of which had an impact on the study participants.

Part (b) Step 1: Given Information

Part (b) Step 2: Explanation

In response to the query, Mr. Starnes devised a study to investigate if the color in which words are printed affects your ability to read them, and whether the words themselves affect your ability to identify the color in which they are printed. Mr. Starnes used a randomized block design in this situation since each participant received two treatments and so formed a block. The other option, a truly randomized design, would necessitate each patient receiving only one therapy, rather than two.

Part (c) Step 1: Given Information

Part (c) Step 2: Explanation

Mr. Starnes devised a study to investigate if the color in which words are printed affects your ability to read them, and whether the words themselves impact your ability to name the color in which they are printed. As a result, random assignment is utilized to make distinct groups of patients as comparable as possible, which is necessary to eliminate confusion. In this example, the order in which the two treatments are administered is chosen at random, ensuring that previous experience has no bearing on the outcome. As a result, when no random assignment occurs, the experience could be a confounding variable.