Question

PART I

The revenue of 200 companies is plotted and found to follow a bell curve. The mean is $647.988 million with a standard deviation of $33.4954 million. Would it be unusual for a randomly selected company to have a revenue between $678.1 and 681.33 million?

1)	It is impossible for a value in this interval to occur with this distribution of data.

2)	We do not have enough information to determine if a value in this interval is unusual.

3)	A value in this interval would be unusual.

4)	A value in this interval is borderline unusual.

5)	A value in this interval is not unusual.

PART II

Fill in the blanks. After conducting research around the country, Ford Motor Company determined that the probability of a randomly selected Ford vehicle on the road being driven by a female is 0.75. If there are 4,968 Ford vehicles in your town, around __________ cars will be driven by females, give or take __________. Assume each car represents an independent trial.

1)	3,726 , 30.52

2)	3,726 , 931.50

3)	30.52 , 3,726

4)	4,968 , 30.52

5)	3,726 , 0.75

PART III

According to a survey conducted by Deloitte in 2017, 0.4702 of U.S. smartphone owners have made an effort to limit their phone use in the past. In a sample of 54 randomly selected U.S. smartphone owners, what is the probability that between 22 and 29 (inclusively) will have attempted to limit their cell phone use in the past?

1)

0.1383

2)

0.0132

3)

0.2756

4)

1.0844

5)

0.7244

Answer 1

I)

since values between $678.1 and 681.33 million are within 2 standard deviation from the mean value

option 5 is correct

A value in this interval is not unusual

ii)

here mean of distribution=μ=np=		3726.00
and standard deviation σ=sqrt(np(1-p))=		30.52

option 1 is correct

iii)

here this is binomial with parameter n=54 and p=0.47022

P(22<=X<=29)=

∑x=ab     (nCx)px(1−p)(n-x)    =

0.7244

option 5) is correct