Minimum Sample Size

The standard IQ test has a mean of 97 and a standard deviation of 18. We want to be 95% certain that we are within 5 IQ points of the true mean. Determine the required sample size.

• 8

• 50

• 1

• 147

The standard IQ test has a mean of 95 and a standard deviation of 17. We want to be 95% certain that we are within 2 IQ points of the true mean. Determine the required sample size.

• 1

• 373

• 278

• 17

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 99% confident that the true mean is within 3 ounces of the sample mean? The standard deviation of the birth weights is known to be 8 ounces.

• 47

• 6

• 48

• 7

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 99% confident that the true mean is within 3 ounces of the sample mean? The standard deviation of the birth weights is known to be 9 ounces.

• 60

• 8

• 7

• 59

It is believed that 60% of the population would prefer smoke-free areas in outdoor concert venues. You want to estimate the proportion of patrons that would like a smoke-free area in your new concert venue to within 6% with 80% confidence. How many people should you survey. Hint - z-star at 80% is 1.282.

• 109

• 110

• 114

• 115

You want to estimate the proportion of residents that would vote in favor of proposed tax changes to within 0.01 with 95% confidence. How many residents should you sample?

• 1500

• 4800

• 4900

• 9604

A 2010 Gallup poll stated that about 74% of young adults said that they were registered to vote. I want to estimate the percent of students at Suffolk University who are registered to vote to within 4% with 95% confidence, how many should I sample?

• 462

• 5

• 6

• 601

European countries report that 46% of the labor force is female. Representatives from the Department of Labor want to estimate the proportion of US employees who are female to within 0.05 with 90% confidence. How many records should they sample?

• 9

• 269

• 382

• 385

Wildlife biologists found that 20% of deer ticks carried Lyme disease last summer. They want to estimate the proportion of deer ticks that carry Lyme disease this year to within 0.08 with 90% confidence. How many ticks should they sample?

• 151

• 97

• 68

• 106

A dermatologist wishes to estimate the proportion of young adults who apply sunscreen regularly before going out in the sun in the summer. Find the minimum sample size required to estimate the proportion to within 0.03, at 90% confidence.

• 88

• 8

• 1068

• 752