MGT 150 Statistics I
Question
MGT 150 Statistics I
Final Exam: Chapters 6, 7 and 8
100 points
Show your work (copy and paste Excel information into Word) to get credit.
Name: ____________________________________________________
(1)True or False: The continuous uniform distribution describes a random variable,
defined on the interval [a, b], that has an equally likely chance of assuming values
within a specified range.
(2)True or False: The normal probability distribution is symmetric and bell-shaped.
(3) An analyst is forecasting net income for Excellence Corporation for the next fiscal
year. Her low-end estimate of net income is $250,000, and her high-end estimate is
$350,000. Prior research allows her to assume that net income follows a continuous
uniform distribution. Find the probability that net income will be greater than or equal to
$337,500.
(4) The time to complete the construction of a soapbox derby car is normally distributed
with a mean of three hours and a standard deviation of one hour. Find the probability
that it would take between 2.5 and 3.5 hours to construct a soapbox derby car.
(5)How many parameters are needed to fully describe any normal distribution and what
are they?
(6) You are considering the risk-return profile of two mutual funds for investment. The
relatively risky fund promises an expected return of 9%, with a standard deviation of
12%. The relatively less risky fund promises an expected return and standard deviation
of 5% and 8%, respectively.
a. Which mutual fund will you pick if your objective is to minimize the probability of
earning a negative return?
b. Which mutual fund will you pick if your objective is to maximize the probability of
earning a return of between 8% and 12%?
(7) Statistics are used to estimate population parameters, particularly when it is
impossible or too expensive to poll an entire population. A particular value of a statistic
is referred to as a(n) _______.
(8) Over the entire six years that students attend an Ohio elementary school, they are
absent, on average, 28 days due to influenza. Assume that the standard deviation over
this time period is ? = 9 days. Upon graduation from elementary school, a random
sample of 36 students is taken and asked how many days of school they missed due to
influenza. What is the expected value for the sampling distribution of the number of
school days missed due to influenza?
(9) Over the entire six years that students attend an Ohio elementary school, they are
absent, on average, 28 days due to influenza. Assume that the standard deviation over
this time period is ? = 9 days. Upon graduation from elementary school, a random
sample of 36 students is taken and asked how many days of school they missed due to
influenza. The probability that the sample mean is less than 30 school days is _______.
(10)Suppose that, on average, electricians earn approximately µ = $54,000 per year in
the United States. Assume that the distribution for electricians’ yearly earnings is
normally distributed and that the standard deviation is ? = $12,000. Given a sample of
four electricians, what is the standard deviation for the sampling distribution of the
sample mean?
(11) True or False: A confidence interval provides a value that, with a certain measure
of confidence, is the population parameter of interest.
(12) What is the most typical form of a calculated confidence interval?
(a) Point estimate ± Standard error
(b) Point estimate ± Margin of error
(c) Population parameter ± Standard error
(d) Population parameter ± Margin of error
(13)In an examination of purchasing patterns of shoppers, a sample of 16 shoppers
revealed that they spent, on average, $54 per hour of shopping. Based on previous
years, the population standard deviation is thought to be $21 per hour of shopping.
Assuming that the amount spent per hour of shopping is normally distributed, find a
90% confidence interval for the mean amount.
(14) For a given confidence level and population standard deviation, which of the
following is true
in the interval estimation of the population mean?
(a) If the sample size is bigger, the interval is narrower.
(b) If the sample size is smaller, the interval is narrower.
(c) If the population size is bigger, the interval is narrower.
(d) If the population size is smaller, the interval is narrower.
(15) Find
for a 99% confidence interval of the population mean based on a
sample of 25 observations
