Chapter 6, Problem 6.1E

(a)

To determine

To identify: Whether the study should be conducted using the experiment or observational study. Also, provide reasons.

Answer to Problem 6.1E

The study should be conducted using the observational study as data can be directly observed from the population without influencing the results.

Explanation of Solution

Given information:

The teacher wants to compare the score of the female students in one group with another group.

Concept used:

In the procedure of observational study, the investigator just observes the participants of the study to draw inferences about the population.

In the procedure of an experimental study, participants are divided into groups randomly where one group receives the actual treatment.

In this case, the teacher can compare the grade average points of both groups of females. Here, the teacher can directly compare the average scores; based on this, one can decide which group has better scores. There is no requirement to conduct the experiment as the teacher can directly observe the scores.

The data collected from this study is not an example of an experiment because the researcher did not divide the participants into two groups. The researcher only observes the participants, indicating that the study is an example of an observational study.

Hence, the desired answer is an observational study.

(b)

To determine

To identify: Whether the study should be conducted using the experiment or observational study. Also, provide reasons.

Answer to Problem 6.1E

The study should be conducted using a randomized experiment as data cannot be directly observed from the population.

Explanation of Solution

Given information:

The doctor wants to compare the efficacy of two allergy medicines.

To find the effect of the two medicines, the researcher should use a randomized experiment. The researcher can collect a sample of a few individuals, assuming a sample of 150 individuals, with each group of 50.

Now the researcher can divide the participants into three groups and two groups should be allocated with the two types of medicines and one group with no medicine. The study's results can be found by comparing all three groups. The effects of the medicine can be identified by comparing the effect of the medicine on allergy for all the groups. Based on the comparison, it can be concluded which medicine is effective and which is not.

Hence, the desired answer is a randomized experiment.

(c)

To determine

To identify: Whether the study should be conducted using the experiment or observational study. Also, provide reasons.

Answer to Problem 6.1E

The study should be conducted using a randomized experiment as data cannot be directly observed from the population.

Explanation of Solution

Given information:

A researcher is interested in identifying whether the server introduces themselves by name to the customers they serve and whether they will receive a larger tip.

The researcher should use a randomized experiment to find the effect of the same name to get more tips from the customer. Here the researcher cannot directly observe the situation and conclude the results; hence observational study cannot be used.

The study results can be found by collecting a sample, assuming a sample of 50 servers can be collected. Then the researcher can instruct one group to use the same name as the customer and the other group servers to use the actual names. After the study, the effects of using the same name can be identified by comparing the tips of both groups. Based on the comparison, it can be concluded whether using the same name effectively gets the higher tip.

Hence, the desired answer is a randomized experiment.

(d)

To determine

To identify: Whether the study should be conducted using the experiment or observational study. Also, provide reasons.

Answer to Problem 6.1E

The study should be conducted using observational study.

Explanation of Solution

Given information:

The researcher is interested in finding whether there is any relationship between the amount of time students spend watching tv and the number of times they bully other students.

In this case, the researcher can directly collect the data for a sample of students, and based on the data researcher can conclude the results. If the number of times students bully other students is higher for those who watch TV for more hours, the relationship can be concluded. There is no requirement to conduct the experiment as the teacher can directly observe the data.

The data collected from this study is not an example of an experiment because the researcher did not divide the participants into two groups. The researcher only observes the participants, indicating that the study is an example of an observational study.

Hence, the desired answer is an observational study.