MATH 210 – Computer Assignment #2 – 25 Points
Due in class on Wednesday, 4/23/08
You will be working with the same partner or group as you did for Computer Assignment #1. (If
there is a reason you need to change groups please contact me first.) You will be using the same
100 data values you previously selected from the CSDATA database for Assignment #1. In this
assignment you will again be analyzing the variables HSM, HSE, SATM and SATV. Use SPSS to
construct confidence intervals and conduct hypothesis tests as indicated below. Type a
double-spaced report summarizing your findings for Purdue computer science majors as they relate
to these four variables. Before doing the analysis use boxplots to identify any outliers and remove
them from your data. If any outliers were removed be sure to indicate this in your report. (You
might want to make a copy of your database before deleting any outliers so you have all the data
available for Computer Assignment #3.) In Parts #1 and 2, use your entire sample of 100, ignoring
the categorical variable SEX. For Parts #3 and 4 you will use the variable SEX to compare males
to females. Follow the procedures in SPSS that we learned in Lab #5.
Your report should begin by summarizing the population being studied and the variables of
interest (see description in text). Also be sure to summarize the statistical methods being used
and your conclusions in the context of this study. Fully explain the meaning of all confidence
intervals and P-values within your typed report. As with Assignment #1 your report should be
well-organized and written in paragraph form. Be sure to follow the general guidelines
provided with Assignment #1. Attach all supporting SPSS output and highlight all relevant
values on your output.
1. For each of the four variables (HSM, HSE, SATM and SATV) construct a 95% confidence
interval for the mean value in the overall population of Purdue C.S. students.
2. For each of the variables perform a hypothesis test (using =.05) to determine if the following
guesses (which will correspond to H0) are correct or not. In each case use a two-tailed (i.e.,
“not equals”) alternative. Be sure to support your conclusions by citing the appropriate P-value
from the software.
Mean HSM = 8.0
Mean SATM = 500
Mean HSE = 8.0
Mean SATV = 500
3. Traditionally, people think (or used to think) males have better math skills and females have
better verbal skills. For each of these four variables conduct a hypothesis test (using =.05)
comparing males to females. The null hypothesis for each test will be that the means for males
and females are equal (H0: μM = μF). The alternative (what you are attempting to show) is that
the above stereotypes hold true for Purdue C.S. majors (at least as measured by high school
grades and the SAT). Thus for HSM and SATM use the one-tailed alternatives HA: μM > μF,
while for HSE and SATV use HA: μM < μF . Note: If your sample means contradict HA just
state this, and conclude there is not evidence for HA. For example if x-barM > x-barF then
there is certainly not evidence to conclude μM < μF.
4. For each of the four variables construct a 90% confidence interval for the difference between
the mean score for the males and the mean score for the females. That is, estimate how much
higher (or lower) the men’s mean is than the women’s mean. Explain how these intervals
relate to the results of the hypothesis tests done in Part #3. Note: The default is 95%
confidence so you will need to change it to 90%.