View the supplemental materials below:
1) Causality versus Correlation
Video: https://www.youtube.com/watch?v=8B271L3NtAw
2) Measures of Central Tendency
Video: https://www.youtube.com/watch?v=k3aKKasOmIw
Video: https://www.youtube.com/watch?v=MRqtXL2WX2M
EXERCISE 5
Now use your knowledge of mean and hopefully good working knowledge of GPA’s (the use of weighted
means) to complete the following. BE SURE TO SHOW YOUR WORK:
Suppose a student earned the following transcript for his Spring 2020 semester:
Statistics (4 credit hour): A
Economics (3 credit hour): B+
US History (3 credit hour): C
Weightlifting (1 credit hour): A
Calculate his Spring 2020 Grade Point Average (GPA). A grade of “A” holds a numerical value of 4, “B+” holds
a value of 3.33, and “C” holds a value of 2. Round to the hundredths’ place.
Suppose That this student has been a student for a number of semesters. His cumulative GPA (NOT including
Spring 2020) for all of his time is 3.6. In cumulative time, he has taken 58 credits (remember NOT to include
Spring 2020). Calculate his cumulative GPA of his entire career, including Spring 2020. Again, round to the
nearest hundredths’ place.
OK… now plan for the upcoming semester, Fall 2020. The student would like to have a GPA of 3.6 at the end
of the Fall semester. He’ll be taking 12 credits. Is it possible? Why or why not?
The basic measures of central tendency for univariate analysis include mean, median, mode, range, and
standard deviation. Please view the videos below for a quick re-fresher. Extremely important: depending on the
nature of the variable (nominal, ordinal, interval/ratio), nature of the variable (dichotomous, continuous) or the
nature of the sample (size, outliers, representativeness), the descriptive statistic most important in
understanding the variable may change. For instance, mean might be extremely telling of the variable or
completely misguided/ virtually non-usable. So typically, there is a “best measure of central tendency” dictated
by variable nature and sample. For example, how would you answer the following two exam questions:
When summarizing heavily skewed data, the best measure of central tendency is:
A friend of yours assigned a code of 1 to “male” and a code of 2 to “female” on the variable sex. Your friend
asked the computer to compute the average score on sex. The computer printout contained the following
information: mean=1.38, standard deviation=.43, median=1.4, and mode=1.0. You advise your friend that the
best measure(s) of central tendency is(are) _.