statistics math homeowork

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QNT 351

No. 4

(Show your work – 30 pts e

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ch)

Name:

QNT 351
2
Quiz No. 4

1- Researchers at the University of Toledo indicate that 50 percent of the students change their major area of study after their first year in a program. A random sample of 100 students in the College of Business revealed that 51 had changed their major area of study after their first year of the program. Has there been a significant increase in the proportion of students who change their major after the first year in this program? Test at the 0.05 level of significance.

2
The management of ABC Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using a 0.05 level of significance, can we conclude that the assembly time using the new method is faster?

3
Last year the records of Dairy Land Inc., a convenience store chain, showed the mean amount spend by a customer was $30. A sample of 40 transactions this month revealed the mean amount spend was $33 with a standard deviation of $12. At the 0.1 level of significance, can we conclude that the mean amount spend has increased?

4
State DMV records indicate that of all vehicles undergoing emissions testing during the previous year, 70% passed on the first try. A random sample of 200 cars tested in a particular county during the current year yields 160 that passed on the initial test. Does this suggest that the true proportion for this county during the current year differs from the previous statewide proportion? Test the relevant hypotheses using

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5
According to a recent survey, Americans get a mean of 7 hours of sleep per night. A random sample of 50 students at Sacramento State University (Sac State) revealed the mean number of hours slept last night was 6.8 hours. The standard deviation of the sample was 0.9 hours. At 10% level of significance, is it reasonable to conclude that students at Sac State sleep less than the typical American?

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