10/19/2009

Statistical Inference 

• Point Estimation
• Confidence Intervals: point estimator ± margin of error

Definition: A 100*C% confidence interval (C.I.) for a parameter (say theta) is given by two statistics  L and U such that P(L<= theta <= U) = C.

• Example - Exercise 9.15 on p. 387

Class Exercises

• The behavior of C.I.'s
  • Simulate the drawing of 50 simple random samples of size 100 from a population with p = 0.6.
  • Use Minitab to calculate the 90% C.I. for the population proportion for each of your 50 samples.
  • Verify the caclulations by checking the interval given for the first sample.
  • How many of your 50 C.I.'s contain the true mean?
• How does this simulation exercise help you interpret confidence intervals?
• 9.17, 9.25, and 9.29

Please read Sections 9.2 and 9.3 for class on Wednesday.