Chapter 9, TwoSample Tests with Numerical Data

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Chapter 10, Comparing Two Related Samples
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Chapter 10, Comparing Two Related Samples t
Test for the Mean Difference
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10.2 Comparing Two Related Samples T Tests for
the Mean Difference

• Classroom exercise 10.27 in class using Excel
• Homework Use Excel to complete steps 1-6 and 10
  for even numbered problems 10.24 through 10.30
• state the null hypothesis and explain its meaning
• state the alternate hypothesis and explain its
  meaning
• write the level of significance (alpha error)
• write the sample size
• Determine appropriate statistical technique and
  corresponding test statistic to use.
• Determine critical value(s) and decision rule.
• Express the statistical decision in terms of the
  story

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10.2 Comparing Two Related Samples T Tests for
the Mean Difference

• Assume you have two fertilizers, Grow Like Crazy
  and Grow Really Fast. You want to know if one
  fertilizer will produce a higher average yield of
  corn per acre.
• What variables do you have in this problem?
• How can you control some of those variables so
  that you can isolate the fertilizer variable?

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Yield per acre
The two sampling distributions may have different
means.
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Yield per acre
The two sampling distributions may have different
means.
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Or, the sampling distributions for Grow Like
Craze and Grow Really Fast may have the same
population mean.

• Is the difference between the sample means close
  enough to zero that we can accept the null
  hypothesis that there is no difference between
  the population means?

• See equation 10.5 on page 324.
• See pages 324 and 325 for null and alternate
  hypotheses.