A poll reported that 65% of adults were satisfied with the job the major airlines were doing. Suppose 12 adults are selected at random and the number who are satisfied is recorded. (a)Find the probability that exactly 7 are satisfied with the airlines. (b)Find the probability that fewer than 5...

1. Does lecithin enhance memory? To test this idea, nine pairs of people matched in terms of age, sex, IQ and neurological status are given capsules containing either lecithin or a placebo at meals for a week. All are scored on a recent memory talk. A higher score indicates better task...

1. If the claim says that the population mean is greater than 200 and the sample mean is 215, we can say that the claim is true even without a formal test.

a survey was conducted two years ago asking college student their top motivations for using a credit card. To determine whether this distribution has changed, you randomly select 425 students and ask each one what the top motivation is for using a credit card. Can you conclude that there has...

"D" size batteries produced by MNM Corporation have had a life expectancy of 87 hours. Because of an improved production process, it is believed that there has been an increase in the life expectancy of its "D" size batteries. A sample of 36 batteries showed...

Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the night shift than on the day shift. Assume the population standard deviation for the number of units produced on the day shift is 21 and is 28 on the night shift. A...

A researcher wants to test whether a certain sound will make rats do worse on learning tasks. It is known that an ordinary rat can learn to run a particular maze correctly in 18 trials, with a standard deviation of 6. (The number of trials to learn this maze is normally distributed.) The...

Consumer Reports gives information about the age at which various household products are replaced. For example, color TV's are replaced at an average age of 8 years after purchase and a standard deviation of 1.5 years. What is the probability that someone will keep a color TV fewer than 10...

Eight pairs of data yield r = 0.708 and the regression equation y = 55.8 + 2.79x. Also, mean y = 71.125. What is the best predicted value of y for x = 5.7?

6. Find the probability that at most 5 defective bolts will be found in a box of 200 bolts if it is known that 2 per cent of such bolts are expected to be defective .(you may take the distribution to be Poisson; e-4= 0.0183).