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A food snack manufacturer samples 15 bags of pretzels off the assembly line and weighed their contents. If the sample mean is 10.0 and the sample standard deviation is 0.15, find the 95% confidence
You play 2 games against the same opponent. The probability you win the 1st game is 0.4, if you win the 1st game the probability you also win the second is 0.2. If you lose the first game, the prob
A previous study of nickels showed that the standard deviation of the weight of nickels is 150 milligrams. How many nickels does a coin counter manufacturer need to weigh so that she can be 98% conf
Which trend model is best, and why? If none is satisfactory, explain. (e) Make a forecast for 2004 by using a trend model of your choice or a judgment forecast.
Retailers report that the use of cents-off coupons is increasing - the proportion of all households that use coupons comes to .64. Suppose that this estimate was based on a random sample of 600 hou
Assume independent events. Why might the assumption of independence be violated? (b) Why might a driver be tempted not to use a seat belt "just on this trip"?
The amount of fluid in a half-liter bottle of diet cola is normally distributed, and from past experience, the standard deviation is known to be 1.20 milliliters. A sample of 50 bottles reveals a me
A manufacturing company has three factories: X, Y, and Z. If one item is selected at random, find these probabilities. It was manufactured at factory Y or factory Z.
Conduct a two-tailed hypothesis test given the following information. The director of human resources at a large firm is comparing the distance traveled to work by employees in their office in downt
A sample of 25 different payroll departments found that the employees worked an average of 310.3 days a year with a standard deviation of 23.8 days. What is the 90% confidence interval for the aver
Conduct a one-tailed hypothesis test given the following information. A test was conducted to determine whether gender of a spokesperson affected the likelihood that consumers would prefer a new pro
You just purchase a dinner and found that there is no napkin in your bag, what is the probability that Jan prepared your order
A manufacturer claims that the average life of its light bulb is 1,200 hours. Assume that the life of all such bulbs has a normal distribution with mean 1,200 hours, and standard deviation 70 hours.
Conduct a two-tailed hypothesis test to determine if the two means are different, with a .10 level of significance.
You read in a book about bridge that the probability that each of the four players is dealt exctly one ace is about 0.11. this means that in every 100 bridge deals each player has one ace exactly 11
A sample of 23 European countries found that the variance on life expectancy was 7.3 years. What is the 95% confidence interval for the variance of life expectancy in Europe
The amount of fluid in a half-liter bottle of diet cola is normally distributed, and from past experience, the standard deviation is known to be 1.20 milliliters. A sample of 50 bottles reveals a m
A quality control engineer selects an SRS of 20 sticks from a large shipment. The engineer is unaware of the fact that 5% of the sticks in the shipment fail to meet specifications. What is the proba
Suppose that you are the director of an insurance adjustment office. your office had just received 128 insurance claims to be processed in the next few days. what is the probability that?
For the following data calculate the mean and standard deviation for the sample. Then calculate both a 95% and a 99% confidence interval for the popular mean.
Construct a 95% confidence interval for the population proportion p of all Twinkle bulbs?
The quality control director for a clothing manufacturer wants to study the effect of machines. If appropriate, use the Tukey-Kramer procedure to examine differences among machines.
To obtain a 95% confidence interval for the proportion of all students at the university favoring the honor code which is 58%, what is the minimum sample size needed if the total width of the confid
Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 64 randomly selected walk
A sample of 23 European countries found that the variance of life expectancy was 7.3 years. What is the 95% confidence interval estimate for the variance of life expectancy in Europe?