Q1:
The probability that a randomly chosen sales prospect will make a purchase is 20%. What is the probability (to three decimal places) that the salesperson will make four or more sales if six sales calls are made on a given day?
0.025
0.017
0.015
0.020
0.013
Q2:
Fifty random shoppers at an electronics store have been interviewed and 35 of them intend to purchase a newly released smart phone. What probability distribution describes this situation and what are its mean and standard deviation of phone sales if we are concerned about 1071 shoppers that day? Compute to the nearest whole number.
Binomial, 50, 35
Poisson, 731, 11
Poisson, 750, 15
Binomial, 750, 15
Poisson, 731, 11
Q3:
Pet Place sells pet food and supplies including a popular bailed hay for horses. When the stock of this hay drops to 20 bails, a replenishment order is placed. The store manager is concerned that sales are being lost due to stockouts while waiting for a replenishment order. It has been previously determined that demand during the lead-time is normally distributed with a mean of 15 bails and a standard deviation of 6 bails. The manager would like to know the probability of a stockout during replenishment lead-time. In other words, what is the probability that demand during lead-time will exceed 20 bails? Compute to 2 decimal places.
Q4:
If the manager of Pet Place wants the probability of a stockout during replenishment lead-time to be no more than 0.05, what should the reorder point be? Compute to the nearest whole number.
Q5:
The central limit theorem is important for all of the following reasons except:
It ensures that the sampling distribution of the sample mean approaches normal as the sample size increases.
It allows us to use information from samples to draw conclusions about population parameters without knowing the shape of the population distribution.
It ensures that the samples we select are random and representative.
It allows us to use the normal distribution in statistical tests on sample means.
None of the above.
Q6:
Which of the following statements is (are) true with respect to the sampling distribution of sample means?
When the population has a normal distribution, the sampling distribution of the sample mean is normally distributed for any sample size.
When the population has an arbitrary distribution, the sampling distribution of the sample mean is normally distributed for any sample size.
In most applications, the sampling distribution of the sample mean can be approximated by a normal distribution whenever the sample size is 30 or more.
In cases where the population is highly skewed or outliers are present, samples of size 30 are sufficient.
In cases where the population is highly skewed or outliers are present, samples of size 50 may be needed.
Q7:
An audio/video equipment discount store has 36 salespeople. Daily dollar sales for individual sellers employed by the store has a normal distribution with a mean of $2000 and a standard deviation of $300. The store's management is going to implement an incentive program awarding a daily bonus to any salesperson who achieves daily sales over $2150. To four decimal places, what is the probability that an individual salesperson will earn a bonus on any given day?
0.3145
0.3125
0.3105
0.3085
0.1915
Q8:
A recent graduate school study of a random sample of 250 US manufacturing companies determined the average financial report preparation time was 68.04 days with a standard deviation of 35.74 days. Calculate to three decimal places the 95 percent confidence interval for the mean report prep time for all US manufacturing companies. Choose the best answer.
[63.001, 75.008]
[63.957, 75.568]
[63.505, 70.414]
[61.612, 74.468]
[63.612, 72.468]
Q9:
Sample mean (xbar) control charts monitor production processes graphically over time using the basic concepts of confidence intervals.
True
False
Q10:
The number of hybrid cars that have been requested for rental from a car rental office during a 50-day sample period is given in the following table.
Demand for Cars Number of Days Probability
3 3 0.06
4 7 0.14
5 12 0.24
6 14 0.28
7 10 0.20
8 4 0.08
sum 50 1.00
What is the expected (mean) number of hybrid rentals per day? Compute to one decimal place. Choose the closest value.
5.7
6.5
4.8
7.2