Download CRACK THE CASE, authored by Dr

CRACK THE CASE, authored by Dr. Nancy DeFrates-Densch, Northern Illinois University
The Statistics Test
Cassandra has a test in her math class this Friday. She has spent the last several evenings
studying the statistical formulae for measures of central tendency and variability, as she knows
they will be covered on the test. To do this she has quizzed herself repeatedly. In the beginning,
she got them confused, but after repeated tries, she can now recite the formulae for each without
fail. She is certain that she will have no problems on the test.
When she receives her test on Friday, the first thing she does is to write down all of the
formulae before she can forget them, certain that will be all she will need to do well on the exam.
After writing down the formulae, she begins reading the test. The first question gives a list of
scores and asks for the mean, median, mode, variance, and standard deviation.
Cassandra anxiously looks at her list of formulae. She knows which formula goes with
which measure—for instance, she knows that the formula for the mean is x/n. The problem is
that she doesn’t know what x means. She is reasonably sure that “/n” means she is to divide by
n, but what is n? When looking at the rest of the formulae, she realizes that she has similar
problems. She stares at the test in dismay. After all that studying and careful memorization, she
can’t complete a single problem on the test.
1. What are the issues in this case?
2. What went wrong for Cassandra?
3. What should she do differently if she wants to do better on her next test?
4. If you were the teacher of Cassandra’s class, how would you help your students to
prepare for this type of test?
5. Which of the following strategies is most likely to help Cassandra on her next statistics
test?
A. Concentrate on learning only one formula at a time.
B. Forget about memorizing the formulae
C. Learn the definitions of mean, median, and mode, variance, and standard
deviation
D. Work practice problems of each type
6. Which of the following teaching strategies would be most likely to help students to do
well on this type of test?
A. Make certain that students understand what the forumulae mean by working
many example problems in class.
B. Quiz students on the definitions of mean, median, mode, variance, and
standard deviation.
C. Quiz students on the formulae
D. Teach students a mnemonic device to help them remember the formulae.