EXAM
The incubation time for Rhode Island Red chicks is normally distributed with mean of
22days and standard deviation of approximately 3 days. If 1000 eggs are being
incubated, how many chicks do we expect will hatch in 19 to 28 days? - Answer -819
chicks
Find the area under the standard normal curve over the interval specified
below.Between z = -2 and z = 1.2 - Answer -0.862
Suppose that more than a decade ago high levels of lead in the blood put 82% of
children at risk. A concerted effort was made to remove lead from the environment.
Suppose, according to a survey, only 9% of children in the United States are at risk of
high blood-lead levels. In a random sample of 100 children taken more than a decade
ago, what is the probability that 70 or more had high blood-lead levels? - Answer -1.000
John runs a computer software store. He counted 120 people who walked by his store
in aday, 50 of whom came into the store. Of the 50, only 21 bought something in the
store.Estimate the probability that a person who walks by the store will come in and
buysomething. Round your answer to the nearest hundredth. - Answer -0.18
Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable
representing annual percent return for the Vanguard Total Stock Index (all Stocks). Let
y be a random variable representing annual return for the Vanguard Balanced Index
(60% stock and 40% bond). For the past several years, assume the following data.
Compute .
x:
15
0
38
24
31
26
27
-15
-15
-24
y:
10
-3
27
18
25
18