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Q
uantitative
R
easoning &
P
roblem
S
olving
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© 2014 Pacific Crest
9. If two researchers collect random samples from the same population, would you expect the variances
for the two data sets be similar? Explain.
10. Why are variance and standard deviation important concepts?
A
Successful Performance
Successful application of your learning looks like this
As you begin to apply what you’ve learned, you should have a good idea of what success looks like.
A SUCCESSFUL
PERFORMANCE
I describe the degree of variation within a set of data. I...
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Construct appropriate graphs and statistics
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Effectively communicate my results
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Determine possible reasonable and unreasonable values based on my findings
D
emonstrate Your Understanding
Apply it and show you know in context!
1. Choose five interesting sets of data from the link available on the companion website. Predict which
of the sets will have the greatest variance. Calculate the standard deviation of each set of data and
explain why your prediction was or was not correct.
2. In the NFL, a running back averages four yards per carry. Have you seen a running back get stopped
essentially three straight times for a loss in yardage or break for long gains back to back? What is
the actual probability of getting yardage between 10 to 14 yards if the variance is small vs. if it were
very high?
3. In the file available on the companion website, there is an example of measuring tolerance in
cylinders being machined for use in vehicle engine blocks. Study the importance of tolerance in
manufacturing. Explain how standard deviation is used to measure tolerance. Determine the standard
deviation and variance for the set of cylinders provided in the file.