Dr. Crawford believes she has invented a pill to help with student memorization. For a trial experiment, she gathered two groups of twenty students. She gave the twenty students in Group A the “smart pill”, and the twenty students in Group B a sugar pill. After waiting five minutes, both groups of students were given a list of forty words, and were instructed to memorize the entire list in any order. The students were given five minutes to memorize the list. The students were then asked to verbally recite all of the words they could remember in any order within three minutes.

Group A recited an average of fifteen words, while Group B recited an average of ten words.

Group B is the _________.

After much success with her initial experiments (i.e. Groups A and B) and pilot test, Dr. Crawford wanted to further test the effects of a “smart pill." She recruited a new group of twenty students, Group C, for this next experiment. In the first trial, she gave the students the smart pill, and then waited five minutes to give them the list of forty words. Students were instructed to memorize the list in any order and were given five minutes to study it. The students were then asked to verbally recite all of the words they could remember within three minutes. One week later, Dr. Crawford repeated the experiment with the same group and same list of words. However, on the second trial, students were given the sugar pill instead of the smart pill.

On the first trial, students from Group C recalled an average of seventeen words. On the second trial, students recalled an average of twenty words.

Which of the following experimental designs best describes this particular study?

After much success with her initial experiments (i.e. Groups A and B) and pilot test, Dr. Crawford wanted to further test the effects of a “smart pill." She recruited a new group of twenty students, Group C, for this next experiment. In the first trial, she gave the students the smart pill, and then waited five minutes to give them the list of forty words. Students were instructed to memorize the list in any order and were given five minutes to study it. The students were then asked to verbally recite all of the words they could remember within three minutes. One week later, Dr. Crawford repeated the experiment with the same group and same list of words. However, on the second trial, students were given the sugar pill instead of the smart pill.

On the first trial, students from Group C recalled an average of seventeen words. On the second trial, students recalled an average of twenty words.

What should Dr. Crawford have done to improve the experiment?

After much success with her initial experiments (i.e. Groups A and B) and pilot test, Dr. Crawford wanted to further test the effects of a “smart pill." She recruited a new group of twenty students, Group C, for this next experiment. In the first trial, she gave the students the smart pill, and then waited five minutes to give them the list of forty words. Students were instructed to memorize the list in any order and were given five minutes to study it. The students were then asked to verbally recite all of the words they could remember within three minutes. One week later, Dr. Crawford repeated the experiment with the same group and same list of words. However, on the second trial, students were given the sugar pill instead of the smart pill.

On the first trial, students from Group C recalled an average of seventeen words. On the second trial, students recalled an average of twenty words.

The students’ improved recall on the second trial is likely due to which of the following?

A researcher is interested in studying the cognitive development of children. She administers an appropriate instrument to three groups of children at a school: 8-year olds, 9-year olds, and 10-year olds. She tests the students only once. This study is an example of a __________.

What is the difference between reliability and validity?

Which of the following statistical tools has one mode and 99.7% of the data falls within three standard deviations of the mean?

A statistician who determines that the independent variable has no effect when it really does have an effect has committed which of the following errors?

Which of the following post hoc tests applies simultaneously to all pairwise comparisons , and is considered conservative if sample sizes are unequal?

Which of the following kinds of diagrams is best to display nominal data?