Questions from Applied Statistics

Q: When told that over a 10-year period a mammogram test

When told that over a 10-year period a mammogram test has a false positive rate of 50 percent, Bob said, “That means that about half the women tested actually have no cancer.” Correct Bob’s mistaken i...

Q: Suppose you always reject the null hypothesis, regardless of any sample

Suppose you always reject the null hypothesis, regardless of any sample evidence. (a) What is the probability of Type II error? (b) Why is this a bad policy?

Q: Suppose the judge decides to acquit all defendants, regardless of the

Suppose the judge decides to acquit all defendants, regardless of the evidence. (a) What is the probability of Type I error? (b) Why is this a bad policy?

Q: A test-preparation company advertises that its training program raises SAT

A test-preparation company advertises that its training program raises SAT scores by an average of at least 30 points. A random sample of test-takers who had completed the training showed a mean incre...

Q: Find the standard normal area for each of the following. Sketch

Find the standard normal area for each of the following. Sketch the normal curve and shade in the area represented below. a. P(Z < -1.96) b. P(Z > 1.96) c. P(Z < 1.65) d. P(Z > -1.65)

Q: Telemarketers use a predictive dialing system to decide whether a person actually

Telemarketers use a predictive dialing system to decide whether a person actually answers a call (as opposed to an answering machine). If so, the call is routed to a telemarketer. If no telemarketer i...

Q: If the true mean is 50 and we reject the hypothesis that

If the true mean is 50 and we reject the hypothesis that μ = 50, what is the probability of Type II error?

Q: Pap smears are a test for abnormal cancerous and precancerous cells taken

Pap smears are a test for abnormal cancerous and precancerous cells taken from the cervix. (a) State a pair of hypotheses and then explain the meaning of a false negative and a false positive. (b) Why...

Q: In a commercially available fingerprint scanner (e.g., for

In a commercially available fingerprint scanner (e.g., for your home or office PC), false acceptances are 1 in 25 million, with false rejection rates of 3 percent. (a) Define Type I and II errors. (b)...

Q: High blood pressure, if untreated, can lead to increased risk

High blood pressure, if untreated, can lead to increased risk of stroke and heart attack. A common definition of hypertension is diastolic blood pressure of 90 or more. (a) State the null and alternat...