Question

A study of undergraduate computer science students examined changes in major after the first year. The study examined the fates of 256 students who enrolled as first-year students in the same fall semester. The students were classified according to gender and their declared major at the beginning of the second year. For convenience we use the labels CS for computer science majors, EO for engineering and other science majors, and O for other majors. The mean SAT mathematics scores for the students are summarized in the following table. Major Gender CS EO O Males 628 618 589 Females 582 631 543 Summarize the results of this study using appropriate plots and calculations to describe the main effects and interaction.

Answer 1

Using the Minitab follow the steps mentioned below:

1.Type or import the data in three columns. One column contains the Gender another contains Major and a third column Means.

2.Click on the Stat tab. Select Anova Main Effects Plot.

3.Select the means in the Responses and Gender and major in the factors.

4.Click OK.

Follow the above instructions to obtain the main effects plot as shown below:

The main effects plot is,

Explanation | Hint for next step

From the Main effects plot for means, the mains effects of gender and major are shown.

The effect of each independent variable, considered by itself, is called a main effect.

Step 2 of 2

Using the Minitab follow the steps mentioned below:

1.Type or import the data in three columns. One column contains the Gender another contains Major and a third column Means.

2.Click on the Stat tab. Select Anova Interaction Plot.

3.Select the means in the Responses and Gender and major in the factors.

4.Mark the display full interaction plot matrix.

5.Click OK.

Follow the above instructions to obtain the main effects plot as shown below:

The interaction plot is,

Explanation

From the interaction plot, the interaction between gender and major are shown.

Interaction is related to the joint effect of the two independent variables.

There is an interaction between the two variables. That means the effect of one factor depends on the levels of the second factor.

The main effects plot is,

The interaction plot is,