Margin of Error Calculations

• 120

• 61

• 69

• 105

• None of the other choices is correct

• 2

• 64

• 4

• 74

• None of the other choices is correct

A research group wishes to estimate the mean amount of time (in hours) that members of a fitness center spend exercising each week. They want to estimate the mean within a margin of error of 0.5 hours with a 95% level of confidence. Previous data suggests that the standard deviation of the population is 2.2. Which of the following is the smallest sample size they could use?

• 60

• 75

• 90

• 180

Consider a camera club with 1800 members, where it is required to estimate the average number of rolls of film used during a year. Consider also the information from the past that the average and standard deviation of the number of rolls of film have been around 6 and 4, respectively.

Find the sample size requerid with a error = 1% and 95% of confidence

• 1750

• 1770

• 1760

• 1780

A survey is to be conducted to estimate the average monthly income of a locality with 5000 households. It is known that the squared variability in the income is 250000 Rayals. How many households should we select so that the marginal error of estimated income is no more than 200 Rayals? use a confidence of 95%

• 21

• 22

• 23

• 24

A study by the department of education in a certain state found that there was a mean SAT score of 534 with a margin of error of 20.

Which score(s) would fall outside the confidence interval?

• 505

• 530

• 550

• 558

A study by the department of education in a certain state found that there was a mean SAT score of 534 with a margin of error of 20.

Create a confidence interval for the true mean.

• (534, 554)

• (514, 534)

• (514, 554)

Determine whether the action would increase or decrease the margin of error:

Increase the sample size

• Margin of error increases

• Margin of error decreases

Determine whether the action would increase or decrease the margin of error:

Increase the confidence level from 95% to 99.7%

• Margin of error increases

• Margin of error decreases

Determine whether the action would increase or decrease the margin of error:

Decrease the confidence level from 95% to 68%

• Margin of error increases

• Margin of error decreases