Page 446: 7, 11, 29b, 33, 35
- For 7 and 11, use today's notes about margin of error! (or, check out page 436 about ME)
- For 29b, remember the "law of diminishing returns..."
- Remember, because of the square root, if we (for example) increase our sample size by 9 times (n x 9), we will only cut our standard deviation (and thus, margin of error) by a factor of 3
- In other words, if we multiply the sample size by 9, we divide the standard deviation/margin of error by 3!
- Use this rule to think about the new sample size you'll need to cut margin error in half! (If we want to divide standard deviation/ME by 2, we have to multiply sample size by...)
- For 33 and 35, you need to find the sample size given a margin of error and C. Level....
- Set up your equation: ME = z*(sqrt(pq/n)
- Substitute values for ME, z*, p-hat and q-hat, then solve for n!
- (Lots of algebra)
- Check out the example (Choosing Sample Size) on page 442!
Tomorrow we'll finish our notes on confidence intervals...see you there!
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