Question

1) If two samples A and B had the same mean and standard deviation, but sample A had a smaller sample size, which sample would have the wider 95% confidence interval? Sample A as it has the smaller sample Sample B as its sample is more disperse Sample A as it comes first Sample B as it has the larger sample

2) Why might a company use a lower confidence interval, such as 80%, rather than a high confidence interval, such as 99%? They track the migration of fish where accuracy is not as important They make children's toys where imprecision is expected They are in the medical field, so cannot be so precise They make computer parts where they are too small for higher accuracy

3) If you were designing a study that would benefit from a narrow range of data points, you would want the input variable to have: a large standard deviation a small mean a small margin of error a small sample size

4) From a random sample of 58 businesses, it is found that the mean time the owner spends on administrative issues each week is 21.69 with a population standard deviation of 3.54. What is the 95% confidence interval for the amount of time spent on administrative issues? (21.78, 22.60) (20.93, 22.46) (19.24, 24.14) (20.71, 22.67)

Answer 1

1) The sample with smaller sample size will have wider confidence interval because as the sample size increases the width of confidence interval decreases and vice-versa.

Ans : Sample A as it has the smaller sample

2) Ans: They track the migration of fish where accuracy is not as important

3) We would want the input variable to have a small sample size.

4)

At = 0.05, critical value, = 1.96

95% confidence interval:

the closest answer to this is (20.71, 22.67)