Deck 6: Conthe Tinuonormausl Disdis Tributionstribution and Other

Question 1

If we know that the length of time it takes a college student to find a parking spot in the library
Parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of
1 minute, 75.8% of the college students will take more than how many minutes when trying to
Find a parking spot in the library parking lot?

A) 2.8 minutes
B) 3.2 minutes
C) 3.4 minutes
D) 4.2 minutes

Answer 1

A

Question 2

A company that receives the majority of its orders by telephone conducted a study to determine
How long customers were willing to wait on hold before ordering a product.The length of
Waiting time was found to be a variable best approximated by an exponential distribution with a
Mean length of waiting time equal to 2.8 minutes (i.e.the mean number of calls answered in a
Minute is 1/2.8).What is the probability that a randomly selected caller is placed on hold fewer
Than 7 minutes?

A) 0.0009119
B) 0.082085
C) 0.917915
D) 0.9990881

Answer 2

C

Question 3

True or False: The probability that a standard normal variable, Z, falls between - 1.50 and 0.81
is 0.7242.

Answer 3

True

Question 4

If we know that the length of time it takes a college student to find a parking spot in the library
Parking lot follows a normal distribution with a mean of 3.5 minutes and a standard deviation of
1 minute, find the probability that a randomly selected college student will find a parking spot in
The library parking lot in less than 3 minutes.

A) 0.3551
B) 0.3085
C) 0.2674
D) 0.1915

Question 5

A company that receives the majority of its orders by telephone conducted a study to determine
How long customers were willing to wait on hold before ordering a product.The length of
Waiting time was found to be a variable best approximated by an exponential distribution with a
Mean length of waiting time equal to 3 minutes (i.e.the mean number of calls answered in a
Minute is 1/3).Find the waiting time at which only 10% of the customers will continue to hold.

A) 2.3 minutes
B) 3.3 minutes
C) 6.9 minutes
D) 13.8 minutes

Question 6

Which of the following about the normal distribution is not true?

A) Theoretically, the mean, median, and mode are the same.
B) About 2/3 of the observations fall within 1 standard deviation from the mean.
C) It is a discrete probability distribution.
D) Its parameters are the mean, , and standard deviation,
.

Question 7

The value of the cumulative standardized normal distribution at Z is 0.8770.The value of Z is

A) 0.18
B) 0.81
C) 1.16
D) 1.47

Question 8

A company that receives the majority of its orders by telephone conducted a study to determine
How long customers were willing to wait on hold before ordering a product.The length of
Waiting time was found to be a variable best approximated by an exponential distribution with a
Mean length of waiting time equal to 2.8 minutes (i.e.the mean number of calls answered in a
Minute is 1/2.8).What proportion of callers is put on hold longer than 2.8 minutes?

A) 0.3679
B) 0.50
C) 0.60810
D) 0.6321

Question 9

The value of the cumulative standardized normal distribution at Z is 0.6255.The value of Z is

A) 0.99
B) 0.40
C) 0.32
D) 0.16

Question 10

True or False: The probability that a standard normal variable, Z, is between 1.50 and 2.10 is the
same as the probability Z is between - 2.10 and - 1.50.

Question 11

The value of the cumulative standardized normal distribution at 1.5X is 0.9332.The value of X is

A) 0.10
B) 0.50
C) 1.00
D) 1.50

Question 12

A company that receives the majority of its orders by telephone conducted a study to determine
How long customers were willing to wait on hold before ordering a product.The length of
Waiting time was found to be a variable best approximated by an exponential distribution with a
Mean length of waiting time equal to 3 minutes (i.e.the mean number of calls answered in a
Minute is 1/3).What proportion of customers having to hold more than 1.5 minutes will hang up
Before placing an order?

A) 0.86466
B) 0.60653
C) 0.39347
D) 0.13534

Question 13

Let X represent the amount of time until the next student will arrive in the library parking lot at
The university.If we know that the distribution of arrival time can be modeled using an
Exponential distribution with a mean of 4 minutes (i.e.the mean number of arrivals is 1/4 per
Minute), find the probability that it will take more than 10 minutes for the next student to arrive
At the library parking lot.

A) 0.917915
B) 0.670320
C) 0.329680
D) 0.082085

Question 14

True or False: The probability that a standard normal variable, Z, is below 1.96 is 0.4750.

Question 15

Let X represent the amount of time till the next student will arrive in the library parking lot at the
University.If we know that the distribution of arrival time can be modeled using an exponential
Distribution with a mean of 4 minutes (i.e.the mean number of arrivals is 1/4 per minute), find
The probability that it will take between 2 and 12 minutes for the next student to arrive at the
Library parking lot.

A) 0.049787
B) 0.556744
C) 0.606531
D) 0.656318

Question 16

If a particular set of data is approximately normally distributed, we would find that
Approximately

A) 2 of every 3 observations would fall between 1 standard deviation around the mean.
B) 4 of every 5 observations would fall between 1.28 standard deviations around the mean.
C) 19 of every 20 observations would fall between 2 standard deviations around the mean.
D) All the above.

Question 17

For some value of Z, the value of the cumulative standardized normal distribution is 0.2090.The
Value of Z is

A) - 0.81
B) - 0.31
C) 0.31
D) 1.96

Question 18

A company that receives the majority of its orders by telephone conducted a study to determine
How long customers were willing to wait on hold before ordering a product.The length of
Waiting time was found to be a variable best approximated by an exponential distribution with a
Mean length of waiting time equal to 3 minutes (i.e.the mean number of calls answered in a
Minute is 1/3).What proportion of customers having to hold more than 4.5 minutes will hang up
Before placing an order?

A) 0.22313
B) 0.48658
C) 0.51342
D) 0.77687

Question 19

For some value of Z, the value of the cumulative standardized normal distribution is 0.8340.The
Value of Z is

A) 0.07
B) 0.37
C) 0.97
D) 1.06

Question 20

In its standardized form, the normal distribution

A) has a mean of 0 and a standard deviation of 1.
B) has a mean of 1 and a variance of 0.
C) has an area equal to 0.5.
D) cannot be used to approximate discrete probability distributions.

Question 21

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be between 13 and 16 seconds?

Question 22

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.The middle 60% of the time lapsed will fall between which two
numbers?

Question 23

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be between 14 and 17 seconds?

Question 24

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be between 14 and 15 seconds?

Question 25

True or False: Any set of normally distributed data can be transformed to its standardized form.

Question 26

True or False: The probability that a standard normal variable, Z, falls between -2.00 and -0.44
is 0.6472.

Question 27

True or False: A worker earns $15 per hour at a plant in China and is told that only 2.5% of all
workers make a higher wage.If the wage is assumed to be normally distributed and the standard
deviation of wage rates is $5 per hour, the mean wage for the plant is $7.50 per hour.

Question 28

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be between 15 and 16 seconds?

Question 29

True or False: Theoretically, the mean, median, and the mode are all equal for a normal
distribution.

Question 30

True or False: A normal probability plot may be used to assess the assumption of normality for a
particular set of data.

Question 31

True or False: If a data set is approximately normally distributed, its normal probability plot
would be S-shaped.

Question 32

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.The middle 86% of the time lapsed will fall between which two
numbers?

Question 33

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be between 13 and 14 seconds?

Question 34

True or False: The "middle spread," that is the middle 50% of the normal distribution, is equal to
one standard deviation.

Question 35

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.The probability is 80% that the time lapsed will be longer than
how many seconds?

Question 36

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.The probability is 20% that the time lapsed will be shorter how
many seconds?

Question 37

True or False: The probability that a standard normal variable, Z, is less than 5.0 is
approximately 0.

Question 38

You were told that the amount of time lapsed between consecutive trades on a foreign stock
exchange market followed a normal distribution with a mean of 15 seconds.You were also told
that the probability that the time lapsed between two consecutive trades to fall between 16 to 17
seconds was 13%.The probability that the time lapsed between two consecutive trades would
fall below 13 seconds was 7%.What is the probability that the time lapsed between two
consecutive trades will be longer than 17 seconds?