1) It is known that 10% of the calculators shipped from aparticular factory are defective. What is the probability thatexactly three of five chosen calculators are defective?
A) 0.00729
B) 0.0081
C) 0.081
D) 0.03
2)For a particular clothing store, a marketing firm finds that16% of $10-off coupons delivered by mail are redeemed. Suppose sixcustomers are randomly selected and are mailed $10-off coupons.What is the expected number of coupons that will be redeemed?
A) 0.81
B) 0.96
C) 3.42
D) 5.04
3)
The GPA of accounting students in a university is known to benormally distributed. A random sample of 20 accounting studentsresults in a mean of 2.92 and a standard deviation of 0.16.Construct the 95% confidence interval for the mean GPA of allaccounting students at this university.
A) 2.92 ± 1.729(0.16/ )
B) 2.92 ± 1.96(0.16/ )
C) 2.92 ± 2.086(0.16/ )
D) 2.92 ± 2.093(0.16/ )
4)
The probability that a normal random variable is less than itsmean is ________.
A) 0.0
B) 0.5
C) 1.0
D) Cannot be determined
5)
A company that produces computers recently tested the battery inits latest laptop in six separate trials. The battery lasted8.23,7.89,8.14,8.25,8.30, and 7.95 hours before burning out in eachof the tests. Assuming the battery duration is normallydistributed, construct a 95% confidence interval for the meanbattery life in the new model.
A) [7.9490, 8.3044]
B) [7.9575, 8.2959]
C) [7.9873, 8.2661]
D) [7.9912, 8.2622]
