Question 1058621: 1.A salesperson makes four calls per day. A sample of 100 days gives the following frequencies of sales volumes.
Number of Sales , Observed Frequency (days)
0 , 30
1 , 32
2 , 25
3 , 10
4 , 3
Total , 100
Records show sales are made to 30% of all sales calls. Assuming independent sales calls, the number of sales per day should follow a binomial distribution. Assume that the population has a binomial distribution with n=4, p=0.30, and x=0,1,2,3, and 4.
(a)Compute the expected frequencies for x=0,1,2,3 and 4 by using the binomial probability function. Combine categories if necessary to satisfy the requirement that the expected frequency should be 5 or more for all categories.
(b)Use the goodness of fit test to determine whether the assumption of a binomial distribution should be rejected. Use = 0.05 and the degree of freedom is k – 1 where k is the number of categories.
2.From a survey of 800 supermarket shoppers, the following data have been accumulated as to their levels of education and their preference of television stations. Test at = 0.05 to determine if the selection of a supermarket is dependent upon the level of education.
Level of Education
Secondary School , Bachelor , Graduate , TOTAL
UNACO , 110 , 190 , 100 , 400
EVERRISE , 80 , 220 , 100 , 400
TOTAL , 190 , 410 , 200 , 800
3.Part variability is critical in the manufafacturing of ball bearings. Large variances in the size of the ball bearings cause bearing failure and rapid wearout. Production standards call for a maximum variance of 0.0001 when the bearing sizes are measured ni inches. A sample iof 15 bearings shows a sample standard deviaiton of 0.14 inches.
(a)Use = 0.10 to determine whether the sample indicates that the maximum acceptable variance is exceeded.
(b)Compute the 90% confidence level estimate of the variance of the ball bearings in the population.
4.The proportion of men and women who selected watching television as their most popular leisure time activity can be estimated from the following sample data.
Gender , sample size , watching television
Men , 800 , 248
Women , 600 , 156
Test for a difference between proportion for the population of men and proportion for the population of women who selected watching television as their most popular leisure time activity. Conduct a hypothesis test and compute the p-value. At = 0.10, what is your conclusion?
Answer by ikleyn(52818)   (Show Source):
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