I am taking a financial statistic courses and I need the answers by
Jan 8, 2006 midnight( I just need simple steps and answers, I don't
need explaination):
5.22.
A study by the National Park Service revealed that 50% of vactioners
going to the Rocky Mountain region visitYellowstone Park, 40% visit
the Tetons, and 35% visit both.
a. What is the probability a vacationer will visit at least one of
these attractions?
b. What is the probability .35 called?
c. Are the events mutually exclusive? Explain.
5.26
All Seasons Plumbing has 2 service trucks which frequently break down.
If the probability the 1st truck is available is .75, the probability
the 2nd truck is available is .50, and the probability both trucks are
available is .30, what is the probability neither truck is available?
5.44
A representative of the EPA wants to select samples from 10 landfills.
The director has 15 landfills from which she can collect samples.
How many different samples are possible?
6.10
In a binomial situation n=5 and pi=.40
Determine the probabilities of the following events using the binomial formula
a. X = 1
b. X = 2
6.22
A manufacturer of window frames knows from long experience that 5% of
the production will have some type of minor defect that will require
an adjustment.
What is the probability that in a sample of 20 window frames:
a. None will need adjustment?
b. At least one will need adjustment?
c. More than two will need adjustment?
6.26
A population consists of 15 items, 10 of which are acceptable.
In a sample of 4 items, what is the probability that exactly 3 are
acceptable? Assume the samples are drawn without replacement.
6.36
Textbook authors and publishers work very hard to minimize the number
of errors in a text.
However, some errors are unavoidable. Mr. J. A. Carmen, statistics
editor, reports that the mean number fo errors per chapter is .8.
What is the probability that there are less than 2 errors in a particular chapter?
7.16
A normal population has a mean of 80.0 and a standard deviation of 14.0
a. Compute the probability of a value between 75.0 and 90.0
b. Compute the probability of a value of 75.0 or less.
c. Compute the probability of a value between 55.0 and 70.0.
7.52
Cruise ships of the Royal Viking line report that 80% of their rooms
are occupied during September.
For a crusie ship having 800 rooms, what is the probability that 665
or more are occupied in September.
8.18
According to an IRS study, it takes an average of 330 minutes for
taxpayers to prepare, copy, and electronically file a 1040 tax form.
A consumer watchdog agency selects a random sample of 40 taxpayers and
finds the standard deviation of the time to prepare, copy and
electronically file form 1040 is 80 minutes.
a. What assumption or assumptions do you need to make about the shape
of the populations?
b. What is the standard error of the mean in this example?
c. What is the liklihood the sample mean is greater than 320 minutes?
d. What is the liklihood the sample mean is between 320 and 350 minutes?
e. What is the liklihood the sample mean is greater than 350 minutes?
9.8
Dr. Patton is a Professor of English. Recently he counted the number
of misspelled words in a group of student essays.
For his class of 40 students, the mean number of misspelled words was
6.05 and the standard deviation 2.44 per essay.
Construct a 95% confidence interval for the mean number of misspelled
words in the population of student essays.
10.10
The following hypothesis were given:
Ho: pi = .40
H1: pi=/= .40
A sample of 120 observations revealed that p = .30. At the .05
significance level, can the null hypothesis be rejected?
a. State the decision rule.
b. Compute the value of the test statistic.
c. What is your decision regarding the null hypothesis?
10.24
The liquid chlorine added to swimming pools to combat algae has a
relatively short shelf life before it losses its effectiveness.
Records indicate that the mean shelf life of a 5-gallon jug of
chlorine is 2160 hours (90 days).
As an experiment, Holdlonger was added to the chlorine to find whether
it would increase the shelf life.
A sample of 9 jugs of chlorine had these shelf lives (in hours):
2159 2170 2180 2179 2160 2167 2171 2181 2185
At the .025 level, has Holdlonger increased the shelf life of the
chlorine?
Estimate the p-value.
11.14
The null & alternate hypothesis are:
Ho: µ1 = µ2
H1: µ1 ? µ2
A random sample of 15 observations from the 1st population revealed a
sample mean of 350 and a sample standard deviation of 12.
A random sample of 17 observations from the 2nd population revealed a
sample mean of 342 and a sample standard deviation of 15.
At the .10 significance level, is there a difference in the population means?
11.22
The federal government recently granted funds for a special program
designed to reduce crime in high-crime areas.
A study of the results of the program in 8 high-crime areas of Miami,
Florida, yielded the following results:
Number of crimes by area
A B C D E F G H
Before 14 7 4 5 17 12 8 9
After 2 7 3 6 8 13 3 5
Has there been a decrease in the number of crimes since the
inaugeration of the program?
Use the .01 significance level. |
