20. The mean age (at inauguration) of all U.S. Presidents is approximately Normally distributed with a mean of 54.6. Barack Obama was 47 when he was inaugurated, which is the 11th percentile of the distribution. Which of the following is closest to the standard deviation of presidents' ages? a. -9.20 b. -6.18 с. 6.18 d. 7.60 e. 9.20
Unitary Method
The word “unitary” comes from the word “unit”, which means a single and complete entity. In this method, we find the value of a unit product from the given number of products, and then we solve for the other number of products.
Speed, Time, and Distance
Imagine you and 3 of your friends are planning to go to the playground at 6 in the evening. Your house is one mile away from the playground and one of your friends named Jim must start at 5 pm to reach the playground by walk. The other two friends are 3 miles away.
Profit and Loss
The amount earned or lost on the sale of one or more items is referred to as the profit or loss on that item.
Units and Measurements
Measurements and comparisons are the foundation of science and engineering. We, therefore, need rules that tell us how things are measured and compared. For these measurements and comparisons, we perform certain experiments, and we will need the experiments to set up the devices.
![None of these
368X8.23= US
e.
20. The mean age (at inauguration) of all U.S. Presidents is approximately Normally distributed with a
mean of 54.6 Barack Obama was 47 when he was inaugurated, which is the 11th percentile of the
distribution. Which of the following is closest to the standard deviation of presidents’ ages?
-9.20
b.
a.
-6.18
с.
6.18
d. 7.60
e.
9.20
21. In 1965, the mean price of a new car was $2,650 and the standard deviation was $1000. In 2011, the
mean was $30,500 and the standard deviation was_$9000. If a Ford Mustang cost $2300 in 1965
and $28,000 in 2011, in which year was it more expensive relative to other cars?
1965, because the standard score is higher than in 201 19 300-2650
1965, because the percentile is higher than in 2011.
2011, because the standard score is higher than in 1965.
2011, because the percentile is higher than in 1965.
We cannot compare the two prices, because we don't know if the prices for each
year are Normally distributed.
a.
1965
b.
28,000-30J00
1000
с.
9000
d.
-.35
.28
e.
22. The customer service department of an online store keeps track of the length of time customers wait
on hold for a representative. The mean wait time is 5 minutes and the standard deviation is 2.3
minutes. Suppose the company wants to change the variable from minutes to seconds exceeding a
target time of 120 seconds. That is, if X is wait time in minutes, the new variable is Y = 60X – 120.
Which of the following are the mean and standard deviation of Y?
Hy =
180; o,-2.3
a.
%3D
С.
Hy = 180; ơ,=138
d.
Hy = 300; o,=2.3
e.
Hy = 300; ơ,=18](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F02c99683-a01b-4e64-96f8-7137fedec6c4%2F9794d1af-4dbb-46e6-a221-13c65ee5d398%2Fv3dggvc_processed.jpeg&w=3840&q=75)
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