Chapter 11, Problem 12PT

a.

To determine

To explain: The reason of doing random assignment in the provided study.

Answer to Problem 12PT

To involve all the variables in the study.

Explanation of Solution

Given:

The table is:

Treatment	No subsequent arrest	Subsequent arrest
Advise and separate	187	25
Citation	181	43
Arrest	175	39

In this study random assignment has been done to involve all the variables in the study and eliminate the effect of any variables which are not involved in the provided study.

b.

To determine

To draw: A graph to show the effectiveness of all three treatments.

Explanation of Solution

Graph:

The graph is constructed as:

  

c.

To determine

To provide: The null and alternative hypotheses.

Explanation of Solution

Calculation:

The null and alternative hypotheses are:

  $\begin{array}{l}{H}_0:p_1=p_2=p_3\\ H_a:\text{ At least one of }{p}_i\text{ is different}\end{array}$

d.

To determine

To draw: The conclusion if the p -value is 0.0796.

Explanation of Solution

Calculation:

The p -value < 0.05. The null hypothesis is rejected. Thus, at 5% significance level there is sufficient evidence to reject the claim that all the proportions are equal.