Test2#17.pdf - Print Test 12:07 AM PRINTABLE VERSION Test 2...

12/12/17, 12 : 07 AM Print Test
Page 1 of 7
PRINTABLE VERSION
Test 2
You scored 24 out of 46
Question 1
Your answer is INCORRECT.
A service center receives an average of 0.8 customer complaints per hour. Management's goal is to
receive fewer than three complaints each hour. Assume the number of complaints follows the Poisson
distribution. Determine the probability that exactly four complaints will be received during the next
eight hours.
a) 0.235
b)
0.116
c)
0.008
d)
0.765
e)
0.999
f)
None of the above.
Question 2
Your answer is CORRECT.
Given the cumulative distribution:
Determine Q1, the first quartile.
F ( x ) =
⎧
⎩
⎨
⎪
⎪
0
x − 1
1
10
1
x < 10
10 ≤ x ≤ 20
x > 20

12/12/17, 12 : 07 AM Print Test
Page 2 of 7
Question 3
Your answer is CORRECT.
The average life a manufacturer's blender is 5 years, with a standard deviation of 1 year. Assuming
that the lives of these blenders follow approximately a normal distribution, find the probability that the
mean life a random sample of 25 such blenders falls between 4.5 and 5.2 years.
Question 4
Your answer is INCORRECT.
An electrical firm manufactures light bulbs that have a length of life that is approximately normally
distributed with a standard deviation of 50 hours. How large a sample is need if we wish to be 95%
confident that we will be within 12 hours of the true mean?

12/12/17, 12 : 07 AM Print Test
Page 3 of 7
9