Chapter 6 Quiz Statistics

You ask 50 people what their favorite pizza topping is and 20 answered pepperoni. If you surveyed 720 people, predict how many would answer pepperoni.

• 216

• 320

• 360

• 288

What is the theoretical probability that a number greater than 4 was rolled on the number cube?

• 1/3 or .333

• 1/2 or .5

• 2/3 or .666

• 1/6 or .1666

What was the experimental probability for rolling a number greater than 4?

• 11/20 or ,55

• 1/3 or .333

• 3/10 or .3

• 9/20 or .45

What was the experimental probability for rolling a number divisible by 3?

• 4/15 or .266

• 9/20 or .45

• 1/10 or .1

• 1/4 or .25

For which number did the experimental probability equal the theoretical probability?

• 3

• 4

• 5

• 6

• 3!
• 210
• 840
• 42

The mean and standard deviation of a random sample of 7 baby orca whales were calculated as 430 pounds and 26.9 pounds, respectively. Assuming all conditions for inference are met, which of the following is a 90 percent confidence interval for the mean weight of all baby orca whales?

Researchers studying the sticky droplets found on spider webs will measure the widths of a random sample of droplets. From the sample, the researchers will construct a 95 percent confidence interval to estimate the mean width of all such droplets. Which of the following statements about a 95 percent confidence interval for the mean width is correct?

• The width of the interval will not be affected if the researchers increase or decrease the number of droplets in the sample.

• The interval will be narrower if the researchers increase the level of confidence to 99 percent.

• The interval will be wider if the researchers decrease the level of confidence to 90 percent.

• The interval will be narrower if the researchers increase the sample size of droplets.

• The interval will be wider if the researchers increase the sample size of droplets.

A certain ambulance service wants its average time to transport a patient to the hospital to be 10 minutes. A random sample of 12 transports yielded a 95 percent confidence interval of 11.8±1.6 minutes. Is the claim that the ambulance service takes an average of 10 minutes to transport a patient to the hospital plausible based on the interval?

• The claim is not plausible because 10 falls outside of the interval.

• The claim is plausible because 10 falls within the interval.

• The claim is not plausible because 10 falls within the interval.

• The claim is plausible because 10 falls within 0.95 units of the interval.

• The claim is plausible because 10 falls outside of the interval.

The manager of a city recreation center wants to estimate the percent of city residents who favor a proposal to build a new dog park. To gather data, the manager will select a random sample of city residents. Which of the following is the most appropriate interval for the manager to use for such an estimate?

• A two-sample z -interval for a difference between population proportions.

• A one-sample z -interval for a sample proportion.

• A one-sample z -interval for a difference between population proportions.

• A one-sample z -interval for a population proportion.

• A two-sample z -interval for a difference between sample proportions.