Math 227 - Statistics » Fall 2020 » Chapter 7 Test

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Question #1
Find the area under the standard normal curve to the right of z = 0.4
A.   0.1234
B.   0.3277
C.   0.3446
D.   0.6554
Question #2
Find the z-score that bound the middle 92% of the area under the standard normal curve
A.   -1.88, 1.88
B.   -1.58, 1.58
C.   -1.69, 1.69
D.   -1.75 , 1.75
Question #3
Find the z-score for which the area to the right is 0.37
A.   0.04
B.   0.33
C.   0.22
D.   0.17
Question #4
A certain car model has a mean gas mileage of 34 miles per gallon (mpg) with a standard deviation 4. A pizza delivery company buys 54 of these cars. What is the probability that the average mileage of the fleet is between 33.3 and 34.3 mpg?
A.   0.0985
B.   0.7088
C.   0.6103
D.   0.3897
Question #5
At a cell phone assembly plant, 85% of the cell phone keypads pass inspection. A random sample of 122 keypads is analyzed. Find the probability that less than 88% of the sample keypads pass inspection.
A.   0.1401
B.   0.1762
C.   0.8599
D.   0.8238
Question #6
The weights of 6-week-old poults (juvenile turkeys) are normally distributed with a mean 8.8 pounds and standard deviation 1.9 pound(s). Find the 34th percentile of the weights.
A.   7.22 lb
B.   9.62 lb
C.   8.02 lb
D.   8.82 lb
Question #7
A bottler of drinking water fills plastic bottles with a mean volume of 1,007 milliliters (mL) and standard deviation 6 mL. The fill volumes are normally distributed. What proportion of bottles have volumes less than 1,015 mL?
A.   1.0000
B.   0.6293
C.   0.9082
D.   0.9251

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