If P(A) = 0.30, P(A or B) = 0.40, and P(A and B) = 0.10, what is P(B)?

In a certain town, 50% of the households own a cellular phone, 40% own a pager, and 20% own both a cellular phone and a pager. The proportion of households that own neither a cellular phone nor a pager is:

Insurance company records indicate that 12% of all teenage drivers have been ticketed for speeding and 9% for going through a red light. If 4% have been ticketed for both, what is the probability that a teenage driver has been issued a ticket for speeding but not for running a red light?

Steven has a box of LED's containing 2 blue ones, 3 white ones, 7 red ones, and 3 green ones. If two LED's are drawn at random from the box without replacement, what is the probability that both LED's are not red?

Which one of these variables is a continuous random variable?

The mean number of customers that make a purchase during the first hour that the store is open is:

The standard deviation of the number of customers that make a purchase during the first hour that the store is open is:

According to a CBS/New York Times poll, 15% of the public have responded to a telephone call-in poll. In a random group of five people, what is the probability that exactly two have responded to a call-in poll?

Find the probability that x = 5

A tax preparation firm wants to estimate the proportion of all taxpayers who wait until the last day to file their taxes. A group of 1000 taxpayers were randomly selected. The results reveal that 100 of them didn't file until the last day. Based on this sample, a 95% confidence interval for p, the proportion of taxpayers who wait until the last day to file their taxes, is (0.08, 0.12). What is the margin of error?

A publishing company is studying the sales of various franchises in their chain of stores. They draw a random sample of 75 stores in the chain and measure the average daily sales. They find the mean daily sales to be $5,670, with a standard deviation of $1,750. Calculate a 90% confidence interval for the true mean daily sales of their stores.

In a survey funded by Burroughs-Welcome, 750 of 1000 adult Americans said they didn't believe they could come down with a certain disease. Construct a 95% confidence interval estimate for the true proportion of adult Americans who don't believe they can contract the disease.

Which of the following is a valid interpretation of a confidence interval?

Suppose some researchers have created a confidence interval and wish to decrease the width of their interval. What are the two ways in which this can be accomplished?

In the computation of a confidence interval, if the sample size is not changed but the confidence level is changed from 99% to 95%, you can expect

Experiments on learning in animals sometimes measure how long it takes mice to find their way through a maze. The mean time is 18 seconds for one particular maze. A researcher thinks that a loud noise will cause the mice to complete the maze faster. She measures how long each of 10 mice takes with a noise stimulus. The appropriate hypotheses for this test are:

In each of the following, the p-value and the significance level (alpha) are given for a hypothesis test.

Which pair of values warrants a rejection of the null hypothesis?

The process of producing pain-reliever tables yields tablets with varying amounts of the active ingredient. It is claimed that the average amount of active ingredient per tablet is at least 200 milligrams. The Consumer Watchdog Bureau suspects that the company is shortchanging customers and tests a random sample of 70 tablets. The mean content of the active ingredient for this sample is 194.3 milligrams, with a standard deviation of 21 milligrams. What is the approximate p-value for the significance test?

A hypothesis test was conducted concerning p = the proportion of all drivers who use high-octane gasoline. The null hypothesis was Ho: p = 0.14, the alternative hypothesis was Ha: p > 0.14, and the P-value was 0.2588. What conclusion should be made?

A service station advertises that its mechanics can change a muffler in only 15 minutes. A consumer group believes it is slower and runs a hypothesis test using 49 cars needing new mufflers. In this sample, the mean changing time is 16.25 minutes with a standard deviation of 3.5 minutes. Is this strong evidence against the 15-minute claim? (In other words, would you reject Ho?)

Bages of a certain brand of tortilla chips claim to have a net weight of 14 ounces. A consumer advocacy group wishes to see if there is any evidence that the mean net weight is less than advertised.

They select 16 bags of this brand at random and finds the net weight of each. They find the the sample mean to be 13.88 oz with a standard deviation of 0.24 oz. Based on this data, we would: