Chapter 4.5, Problem 155E

a.

To determine

Identify whether it is best assessed using a confidence interval or a hypothesis test or whether statistical inference is not relevant to answer for the percent of voters in Country U support instituting a national kindergarten through 12^th grade math curriculum.

Explanation of Solution

Since this is about estimating the percentage of voters who support instituting a national kindergarten through 12^th math curriculum, this is relevant to a statistical inference. Also, there is no claim about the population parameter in this study. Therefore, it is best assessed using a confidence interval.

b.

To determine

Identify whether it is best assessed using a confidence interval or a hypothesis test or whether statistical inference is not relevant to answer to check whether basketball players hit a higher proportion of free throws when they are playing at home than when they are playing away.

Explanation of Solution

The aim of the study is to test whether basketball players hit a higher proportion of free throws when they are playing at home than when they are playing away. Here, the null and alternative hypotheses for the claim of the test are as follows:

$\begin{array}{l}{H}_0:p_h=p_a\\ H_a:p_h>p_a\end{array}$

Since there is a claim for the test, it is best assessed using a hypothesis test.

c.

To determine

Identify whether it is best assessed using a confidence interval or a hypothesis test or whether statistical inference is not relevant to answer to check whether a majority of adults riding a bicycle wear a helmet.

Explanation of Solution

The aim of the study is to test whether a majority of adults riding a bicycle wear a helmet or not. Here, the null and alternative hypotheses for the claim of the test are as follows:

$\begin{array}{l}{H}_0:p=0.5\\ H_a:p>0.5\end{array}$

Since there is a claim for the test, it is best assessed using a hypothesis test.

d.

To determine

Identify whether it is best assessed using a confidence interval or a hypothesis test or whether statistical inference is not relevant to answer whether the average of 23 players on the 2014 Canadian Olympic hockey team is older than the 23 players on the 2014 US Olympic hockey team.

Explanation of Solution

Here, the average age of 23 players of both the teams of interest is given. Thus, the two teams represent the population of the study. Since there is information about the population available, statistical inference is not relevant in this case.