Recall that a bank manager has developed a new system to reduce the time customers spend waiting to be served by tellers during peak business hours. The mean walting time during peak business hours under the current system is roughly 9 to 10 minutes. The bank manager hopes that the new system will have a mean waiting time that is less than six minutes. The mean of the sample of 104 bank customer waiting times is 5.48. If we let u denote the mean of all possible bank customer waiting times using the new system and assume that a equals 2.47: (a) Calculate 95 percent and 99 percent confidence intervals for u. (Round your answers to 3 decimal places.) 95 percent confidence intervals for uis 99 percent confidence intervals for u is (b) Using the 95 percent confidence interval, can the bank manager be 95 percent confident that uis less than six minutes? Explain. 05 percent interval is (c) Using the 99 percent confidence interval, can the bank manager be 99 percent confident that u is less than six minutes? Explain. 99 percent interval extends 6.

Americans spend an average of 23.6 hours per week online, with a standard deviation of 7. The distribution of internet watching is not necessarily normally distributed. Suppose you took a random sample of 50 people. What is the probability that the sample average will be less than 23 hrs? Round your answer to three decimal places, eg 0.628.

Userif X represents a random variable coming from a normal distribution with mean 5 and it P(X > 6,5) = 0.35 then P(5 < x < 6.5) = 0.15

Using the normal distribution table find Z0 such that: P(Zz Zo) = .0918 2.57 1.33 1.64 1.87

Suppose x~n(8,9). What value of x is 0.67 standard deviations to the left of the mean?

During an evolution, the minimum, maximum, and average fitness of a population is 1.2, 270, and 40, respectively. If the most fit individual is to be 3 time more likely than the average fit individual to be selected, and the least fit individual is 1/3 as likely as the average fit individual to be selected, what is the scaled fitness of an individual whose raw fitness is 58.

An estimator () is said to be a consistent estimator if the bias of (✔) goes to zero as the sample size gets larger and larger and the variance goes to zero. O True False

The cost C(Q) of producing a quantity Q of widgets to satisfy demand isC(Q) = 4000+20Q, but the quantity demanded is random. If the mean and standarddeviation of demand are 500 and 200, respectively, then what are the mean andstandard deviation of costs?

A bakery has determined that the number of loaves of its white bread demanded daily has a normal distribution with mean 7,200 loaves and standard deviation 300 loaves. Based on cost considerations, the company has decided that its best strategy is to produce a sufficient number of loaves so that it will fully supply demand on 94% of all days. a. How many loaves of bread should the company produce? b. Based on the production in part (a), on what percentage of days will the company be left with more than 500 loaves of unsold bread?

The weights of newborn baby boys born at a local hospital are believed to have a normal distribution with a mean weight of 3939 grams and a standard deviation of 555 grams. If a newborn baby boy born at the local hospital is randomly selected, find the probability that the weight will be less than 4771 grams. Round your answer to four decimal places.