MATH221 Week 4 Quiz| Questions & Answers
(Complete Solutions 100% Correct)
A process is normally distributed with a mean of 104 rotations per minute and a
standard deviation of 8.2 rotations per minute. If a randomly selected minute has 129
rotations per minute, would the process be considered in control or out of control? -
✔✔Out of control as this one data point is more than three standard deviations from
the mean
The soup produced by a company has a salt level that is normally distributed with a
mean of 5.4 grams and a standard deviation of 0.3 grams. The company takes readings
of every 10th bar off the production line. The reading points are 5.8, 5.9, 4.9, 5.2, 5.0,
4.9, 6.2, 5.1, 5.7, 6.1. Is the process in control or out of control and why? - ✔✔It is in
control as the data points more than 2 standard deviations from the mean are far apart
The blenders produced by a company have a normally distributed life span with a mean
of 8.2 years and a standard deviation of 1.3 years. The company is willing to have a
warranty that replaces at most 6% of their blenders sold. What is the longest a blender
can last and still be in the lowest 6% of life spans? - ✔✔6.2 years
A puck company wants to sponsor the players with the 20% quickest goals in hockey
games. The times of first goals are normally distributed with a mean of 8.54 minutes and
a standard deviation of 4.91 minutes. How fast would a player need to make a goal to
be sponsored by the puck company? - ✔✔4.41 minutes
A stock's price fluctuations are approximately normally distributed with a mean of
$104.50 and a standard deviation of $23.62. You decide to purchase whenever the price
reaches its lowest 10% of values. What is the most you would be willing to pay for the
stock? - ✔✔$74.23
, The times that customers spend in a book store are normally distributed with a mean of
39.5 minutes and a standard deviation of 15.9 minutes. A random sample of 60
customers has a mean of 36.1 minutes. Would this outcome be considered unusual, so
that the store should reconsider its displays? - ✔✔Yes, the probability of this
outcome at 0.049, would be considered unusual, so the display should be redone
The weights of ice cream cartons are normally distributed with a mean weight of 20
ounces and a standard deviation of 0.5 ounces. You randomly select 25 cartons. What is
the probability that their mean weight is greater than 20.06 ounces? - ✔✔0.274
Recent test scores on the Law School Admission Test (LSAT) are normally distributed
with a mean of 162.4 and a standard deviation of 10.7. What is the probability that the
mean of 8 randomly selected scores is less than 161? - ✔✔0.356
The mean annual salary for intermediate level executives is about $74000 per year with
a standard deviation of $2500. A random sample of 36 intermediate level executives is
selected. What is the probability that the mean annual salary of the sample is between
$71000 and $73500? - ✔✔0.115
In captivity, a male lion grows to weight about 420 lbs with a standard deviation of 35
lbs. A zoo would like to have a lion that is in the largest 10% of male lions based on
weight. How much should a male lion weigh for the zoo to obtain the male lion? -
✔✔464.9
The average area of a bedroom in a home is 219 square feet with a standard deviation
of 32.5 square feet. What is the largest a bedroom can be and be among the smallest
25% of bedrooms in a home? - ✔✔197.1 sq ft
The speed of cars on a stretch of road is normally distributed with an average 51 miles
per hour with a standard deviation of 5.9 miles per hour. What is the probability that a
randomly selected car is violating the speed limit of 50 miles per hour? - ✔✔0.43
(Complete Solutions 100% Correct)
A process is normally distributed with a mean of 104 rotations per minute and a
standard deviation of 8.2 rotations per minute. If a randomly selected minute has 129
rotations per minute, would the process be considered in control or out of control? -
✔✔Out of control as this one data point is more than three standard deviations from
the mean
The soup produced by a company has a salt level that is normally distributed with a
mean of 5.4 grams and a standard deviation of 0.3 grams. The company takes readings
of every 10th bar off the production line. The reading points are 5.8, 5.9, 4.9, 5.2, 5.0,
4.9, 6.2, 5.1, 5.7, 6.1. Is the process in control or out of control and why? - ✔✔It is in
control as the data points more than 2 standard deviations from the mean are far apart
The blenders produced by a company have a normally distributed life span with a mean
of 8.2 years and a standard deviation of 1.3 years. The company is willing to have a
warranty that replaces at most 6% of their blenders sold. What is the longest a blender
can last and still be in the lowest 6% of life spans? - ✔✔6.2 years
A puck company wants to sponsor the players with the 20% quickest goals in hockey
games. The times of first goals are normally distributed with a mean of 8.54 minutes and
a standard deviation of 4.91 minutes. How fast would a player need to make a goal to
be sponsored by the puck company? - ✔✔4.41 minutes
A stock's price fluctuations are approximately normally distributed with a mean of
$104.50 and a standard deviation of $23.62. You decide to purchase whenever the price
reaches its lowest 10% of values. What is the most you would be willing to pay for the
stock? - ✔✔$74.23
, The times that customers spend in a book store are normally distributed with a mean of
39.5 minutes and a standard deviation of 15.9 minutes. A random sample of 60
customers has a mean of 36.1 minutes. Would this outcome be considered unusual, so
that the store should reconsider its displays? - ✔✔Yes, the probability of this
outcome at 0.049, would be considered unusual, so the display should be redone
The weights of ice cream cartons are normally distributed with a mean weight of 20
ounces and a standard deviation of 0.5 ounces. You randomly select 25 cartons. What is
the probability that their mean weight is greater than 20.06 ounces? - ✔✔0.274
Recent test scores on the Law School Admission Test (LSAT) are normally distributed
with a mean of 162.4 and a standard deviation of 10.7. What is the probability that the
mean of 8 randomly selected scores is less than 161? - ✔✔0.356
The mean annual salary for intermediate level executives is about $74000 per year with
a standard deviation of $2500. A random sample of 36 intermediate level executives is
selected. What is the probability that the mean annual salary of the sample is between
$71000 and $73500? - ✔✔0.115
In captivity, a male lion grows to weight about 420 lbs with a standard deviation of 35
lbs. A zoo would like to have a lion that is in the largest 10% of male lions based on
weight. How much should a male lion weigh for the zoo to obtain the male lion? -
✔✔464.9
The average area of a bedroom in a home is 219 square feet with a standard deviation
of 32.5 square feet. What is the largest a bedroom can be and be among the smallest
25% of bedrooms in a home? - ✔✔197.1 sq ft
The speed of cars on a stretch of road is normally distributed with an average 51 miles
per hour with a standard deviation of 5.9 miles per hour. What is the probability that a
randomly selected car is violating the speed limit of 50 miles per hour? - ✔✔0.43
