Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
REVIEW PROBLEMS FOR THE FINAL EXAM SM221
1. Suppose that one wishes to determine whether the proportions of BU students watching
Monday Night Football (MNF) has changed from last years proportion of .1 (i.e., 10%). If
one takes a random sample of 400 BU s
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Review Problems Exam #2
1. The time it takes to drive from BU to Newton Centre on a weekday morning is normally
distributed with a mean, = 24 minutes and a standard deviation, = 8 minutes. What
proportion of the drive times will be under 34 minutes?
2. In
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Two Sample Test Practice
J)
Baseballs in Major League Baseball games last an average of six pitches. The MLB would
like to determine if the average number of baseballs used per game has changed in the past
five years. Five years ago, in looking at data fr
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
SM221
Practice Problem A
A hotdog vendor on the corner of East and Main does a booming business between 11:30 and
2:00 every day of the work week. Ed, the hotdog vendor, prides himself with offering a wide
variety of toppings on his hotdogs which include:
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
PRACTICE PROBLEM (E)
A battery manufacturer has designed a car battery to last 3 years (36 months) on average. The
company periodically takes samples form the production line to ensure quality. If the standard
deviation is known to be 2 months and the com
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Practice
Scores for an aptitude test for a manufacturing job are normally distributed with a standard
deviation of 12. A sample of 64 tests were analyzed and found that the mean score for this
sample was 48.
a) What is the value of the standard error?
b)
SM221
STATISTICALANDECONOMICDECISIONMAKING
Fall2013
MarkG.Kean
595Commonwealth,#606
Tel:6173534164
email:bird33@bu.edu
COURSEOBJECTIVES
A.
B.
C.
D.
Introducebasicconceptsandtechniquesinprobabilityandstatisticswhich:
1.canbeusedandare,infact,usedinmanyothe
Review Problems Exam #2
1. The time it takes to drive from BU to Newton Centre on a weekday morning is
normally distributed with a mean, = 24 minutes and a standard deviation, = 8
minutes. What proportion of the drive times will be under 34 minutes?
2. In
SM 221 Practice Questions for Exam #1
1. A city has variable weather during the fall. It rains on 20% of the days. Also. its
cold on 25% of the days. Assume rainfall and whether its cold are independent.
What is the probability that a given day will be ei
REVIEW PROBLEMS FOR THE FINAL EXAM SM221
1. Suppose that one wishes to determine whether the proportions of BU students watching
Monday Night Football (MNF) has changed from last years proportion of .1 (i.e., 10%). If
one takes a random sample of 400 BU s
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Errors Practice
G) A local Chinese restaurant delivers Kung Po Chicken and Spring Rolls to area businesses
using bicycles. On average it takes 35 minutes to deliver an order. The manager wants to
decrease this time and decides to give his delivery staff m
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
2 Test of Goodness of Fit Practice
L) A local toll booth has four lanes. Two of them are for EZ Pass and each should support
twice as many cars as the attendant stations. The manager wants to test this hypothesis at the
.10 significance level and tallies
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
2 Test of Independence Practice
N) Researchers would like to know if there is a relationship between gender and whether a
person watches Monday Night Football (MNF). A group of men were polled and 87 did
watch and 35 did not. For a sample of women, 67 wat
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Poisson Practice
Bills Quick Mart sells sandwiches from 122 every week day. The distribution follows a
Poisson distribution with a mean of 5 sandwiches per hour. Use Excel commands
a) What is the probability that Bill will sell more than 13 sandwiched on
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Normal Practice
The average weight or a crate of oranges that arrive at Teds Market is normally distributed with
a mean of 42 pounds and a standard deviation of 3 pounds.
a) What is the probability that a random crate weighing more than 48 pounds?
Excel
A
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
More Review Problems Exam #2
1. Suppose we have a population with mean of 10 and standard deviation of 2. If
we randomly sample n = 64, what is the probability that sample mean, xbar,
exceeds 11? (Excel Command)
2. Using the same information from problem
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Hypothesis of Proportions Practice
D) From past data, the proportion of first graders in New England who write letters to Santa
is 43%. With the US economy coming out of a recession, a group of BU students would
like to know if the rate had increased. The
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Hypothesis of the Means Practice
A) It is known from past experience that the mean number of tennis balls used by the BU
tennis team in a season is 256 with a standard deviation of 16. Due to Superstorm Sandy
you would like to test if there has been a cha
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Practice Questions
Problem #1:
You are the manager of a restaurant that delivers pizzas to college dormitory
rooms. On average it takes 25 minutes to deliver an order. You have recently hired an
operations expert to try to decrease the delivery time. From
Probabilistic and Statistical Decision Making for Managemen
SM 221

Fall 2012
Practice Questions
Problem #1:
You are the manager of a restaurant that delivers pizzas to college dormitory
rooms. On average it takes 25 minutes to deliver an order. You have recently hired an
operations expert to try to decrease the delivery time. From
Chapter2
1. Quantitative: the most recent year percentage increase in the stock, total revenues.
Qualitative: industry, country.
2. Quantitative, qualitative, qualitative. Social security number could be viewed as qualitative
if it is simply used as a lab