Question

problems 4, 5, 6, 11 and 13

If the population standard deviation was doubled to 10.4 and the level of confidence remained at 90%, what would be the new margin of error and confidence interval Margin of error, E. Confidence interval: 20.11<x<34.31 O Did the confidence interval increase or decrease and why? increase 4. Definition of Confidence Intervals (Section 6.1) Circle your answer, True of False. • A 99% confidence interval means that there is a 99% probability that the population mean, h, is in the interval. True/False • A 90% confidence interval means that if a large number of samples are taken, 90% of these samples would contain the actual mean, ul. True / False 5. A nurse at a local hospital is interested in estimating the birth weight of infants. How large a sample must she select if she desires to be 95% confident that the true mean is within 3 ounces of the sample mean? The population standard deviation of the birth weights is known to be 6 ounces. (Section 6.1) - n=(Zco)?

Answer 1

4. A 99% confidence interval means that we would expect 99% of the interval estimates to include the population mean.
The given statement is False

The same explanation as above. The given statement is True

5. We will use the formula for the sample size:

n = (zσ/E)²

Here, E is the margin of error = 3

Standard deviation of the population = 6

z = 1.96

n = (1.96*6/3)² = 15.36

n should be 16

6. In this case,

E = 15

Standard deviation = 30

z = 2.58 (99% confidence)

n = (2.58*30/15)² = 26.62

n should be 27