Probability and Statistics for Engineering and
the Sciences (9th Ed., 2016) – Solutions
Manual – Devore
.0062 - answers-A certain manufacturing plant has a 4% defective rate. Find the probability that
if you choose 1000 units at random, the number of defective units exceeds 55.
.0643 - answers-Suppose that replacement times for washing machines are normally distributed
with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that 70
randomly selected washing machines will have a mean replacement time less than 9.1 years.
.2177 - answers-The weekly salaries of teachers in one state are normally distributed with a
mean of $490 and a standard deviation of $45. What is the probability that a randomly selected
teacher earns more than $525 a week?
.2119 - answers-Estimate the probability of getting at least 15 heads when you flip a coin 25
times.
.6730 - answers-The weights of the fish in a certain lake are normally distributed with a mean of
17 pounds and a standard deviation of 6. If 4 fish are randomly selected, what is the probability
that the mean weight will be between 14.6 and 20.6 lb?
.1199 - answers-Find the probability that in 50 tosses of a deca-die (ten sided), we will obtain
exactly three sevens.
.1190 - answers-Suppose that replacement times for washing machines are normally distributed
with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that a
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the Sciences (9th Ed., 2016) – Solutions
Manual – Devore
.0062 - answers-A certain manufacturing plant has a 4% defective rate. Find the probability that
if you choose 1000 units at random, the number of defective units exceeds 55.
.0643 - answers-Suppose that replacement times for washing machines are normally distributed
with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that 70
randomly selected washing machines will have a mean replacement time less than 9.1 years.
.2177 - answers-The weekly salaries of teachers in one state are normally distributed with a
mean of $490 and a standard deviation of $45. What is the probability that a randomly selected
teacher earns more than $525 a week?
.2119 - answers-Estimate the probability of getting at least 15 heads when you flip a coin 25
times.
.6730 - answers-The weights of the fish in a certain lake are normally distributed with a mean of
17 pounds and a standard deviation of 6. If 4 fish are randomly selected, what is the probability
that the mean weight will be between 14.6 and 20.6 lb?
.1199 - answers-Find the probability that in 50 tosses of a deca-die (ten sided), we will obtain
exactly three sevens.
.1190 - answers-Suppose that replacement times for washing machines are normally distributed
with a mean of 9.3 years and a standard deviation of 1.1 years. Find the probability that a
1
