Microsoft Office Tutorials and References
In Depth Information
Problems and Exercises
1. What is the difference between time series and cross-sectional data? Give
examples of both?
2. What are the three principle approaches we discussed for performing data
analysis in Excel?
3. What is a frequency distribution?
4. Frequency distributions are often of little use with time series data. Why?
5. What are three statistics that provide location information of a frequency
distribution?
6. What are two statistics describing the dispersion or variation of frequency
distributions?
7. What does a measure of positive skewness suggest about a frequency distribu-
tion?
8. If a distribution is perfectly symmetrical, what can be said about its mean,
median, and mode?
9. How are histograms and frequency distributions related?
10. What is the difference between a sample and a population?
11. Why do we construct confidence intervals?
12. Are we more of less confident that a sampling process will capture the true
population mean if the level confidence is 95 or 99%?
13. What happens to the overall length of a confidence interval as we are required
to be more certain about capturing the true population mean?
14. What is the difference between an independent variable and dependent variable
in regression analysis?
15. You read in a newspaper article that a Russian scientist has announced that he
can predict the fall enrollment of students at Inner Mongolia University (IMU)
by tracking last spring’s wheat harvest in metric tons in Montana, USA.
a. What are the scientist’s independent and dependent variables?
b. You are dean of students at IMU, so this announcement is of importance for
your planning. But you are skeptical, so you call the scientist in Moscow to
ask him about the accuracy of the model. What measures of fit or accuracy
will you ask the scientist to provide?
16. The Russian scientist provides you with an alpha (1040) and a beta (38.8) for
the regression. If the spring wheat harvest in Montana is 230 metric tons, what
is your prediction for enrollment?
17. The Russian scientist claims the sum of all residuals for his model is zero and
therefore it is a perfect fit. Is he right? Why or why not?
18. What Significance F would you rather have if you are interested in having a
model with a significant association between the independent and dependent
variables—0.000213 or 0.0213?
19. In the covariance matrix below, answer the following questions:
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