Chapter 10.3, Problem 99E

(a)

To determine

To state which inference procedure you would use in the following question.

Answer to Problem 99E

One-sample z interval is used.

Explanation of Solution

The researchers wants to study about the drowning in the bath tub of the children and they conducted the study over parents and asked many questions. They wants to estimate the percentage of all children who uses the baby bath tub.

When we are using a hypothesis test or confidence interval for the proportion we use z test/interval and when we are using a hypothesis test or confidence interval for the mean we use t test/ interval.

Now, we have been given one sample while we are interested in estimating the proportion that said they used baby bathtubs for infants. So we will use One-sample z interval for proportion.

(b)

To determine

To state which inference procedure you would use in the following question.

Answer to Problem 99E

Paired t test for the mean difference is used.

Explanation of Solution

Researchers wants to study about how seriously do people view speeding vehicle in comparison with other annoying behavior.

When we are using a hypothesis test or confidence interval for the proportion we use z test/interval and when we are using a hypothesis test or confidence interval for the mean we use t test/ interval.

Thus, we have given two samples while we are interested in determining if the claim that the speeding drivers get a higher average rating than the noisy neighbors. Since two samples contain the same subjects thus they are relatable. So, we will use Paired t test for the mean difference.

(c)

To determine

To state which inference procedure you would use in the following question.

Answer to Problem 99E

Two- samplez interval for the difference in proportions is used.

Explanation of Solution

The researcher wants to estimate the difference in the percents of students from rural background among dropouts and graduates.

When we are using a hypothesis test or confidence interval for the proportion we use z test/interval and when we are using a hypothesis test or confidence interval for the mean we use t test/ interval.

Thus, we are given two samples while we are interested in estimating the difference in percents for the students from rural backgrounds among the dropouts and graduates. Since two samples contain different subjects and they both are independent then we will use Two-sample z interval for the difference in proportions.

(d)

To determine

To state which inference procedure you would use in the following question.

Answer to Problem 99E

Two-sample t test for the difference in means is used.

Explanation of Solution

We have to find out do the experienced computer gamers get higher scores when they play with someone present to cheer them on or when they play alone.

When we are using a hypothesis test or confidence interval for the proportion we use z test/interval and when we are using a hypothesis test or confidence interval for the mean we use t test/ interval.

Thus, we are given two samples while we are interested in determining if the claim that experienced computer game players earned higher scores when they play with someone present to cheer them on or when they play alone. Since the two samples contain different subjects and they are independent then we should use Two-sample t test for the difference in means.