Questions from Applied Statistics

Q: In a certain city, 8 percent of the cars have a

In a certain city, 8 percent of the cars have a burned-out headlight. (a) What is the expected number that must be inspected before the first one with a burned-out headlight is found? (b) What is the...

Q: Historically, 5 percent of a mail-order firm’s regular charge

Historically, 5 percent of a mail-order firm’s regular charge-account customers have an incorrect current address in the firm’s computer database. (a) What is the expected number of customer orders un...

Q: In the Ardmore Hotel, 20 percent of the customers pay by

In the Ardmore Hotel, 20 percent of the customers pay by American Express credit card. (a) Of the next 10 customers, what is the probability that none pay by American Express? (b) At least two? (c) Fe...

Q: Find the standard normal area for each of the following, showing

Find the standard normal area for each of the following, showing your reasoning clearly and indicating which table you used. a. P(-1.22 < Z < 2.15) b. P(-3.00 < Z < 2.00) c. P(Z < 2.00) d. P(Z = 0)...

Q: For patients aged 81 to 90, the probability is .07

For patients aged 81 to 90, the probability is .07 that a coronary bypass patient will die soon after the surgery. (a) What is the expected number of operations until the first fatality? (b) What is t...

Q: The self-reported number of hours worked per week by 204

The self-reported number of hours worked per week by 204 top executives is given below. (a) Estimate the mean, standard deviation, and coefficient of variation using an Excel worksheet to organize you...

Q: How long does it take to fly from Denver to Atlanta on

How long does it take to fly from Denver to Atlanta on Delta Airlines? The table below shows 56 observations on flight times (in minutes) for the first week of March 2005. (a) Use the grouped data for...

Q: A random sample of individuals who filed their own income taxes were

A random sample of individuals who filed their own income taxes were asked how much time (hours) they spent preparing last year’s federal income tax forms. (a) Estimate the mean. (b)...

Q: This table shows the distribution of winning times in the Kentucky Derby

This table shows the distribution of winning times in the Kentucky Derby (a horse race) over 84 years. (a) From the grouped data, calculate the mean. Show your calculations clearly in a worksheet. (b)...

Q: If we fail to reject the null hypothesis that π = .

If we fail to reject the null hypothesis that π = .50 even though the true proportion is .60, what is the probability of Type I error?