229 CP 24
Determining Appropriate Two Sample Statistic
1.
Do male and female students study the same amount per week? In a recent year, 58 sophomore
business students were surveyed at a large university that has more than 1,000 business students
each year

229 CP 21
Two Sample Tests and Comparing the Means of Two Related Samples
1.
An experimental design for a paired t test has 25 pairs of identical twins. How many degrees of freedom
are there in this t test? 24 degrees of freedom
2.
Target vs Walmart: who

229 CP 16 Problems
Hypothesis Testing Methodology
1.
If you use a 0.05 level of significance in a two-tailed hypothesis test. What decision will you make if Zstat
= -0.76? Do not reject the null hypothesis
2.
If you use a 0.05 level of significance in a t

BIA 229 CP2
1.
Who goes to the train the trainers workshop?
A firm has the following 30 junior associates and 10 senior associates. The need to select 4 junior
associates and 2 senior associates.
Junior Associates
1 Chen
5 Pearl
9 Ghosh
13 Shank
17 Robert

229 CP 13
Confidence Interval Estimation
X = 85, = 8, n = 64, construct a 95% confidence interval estimate for the population mean, .
83.04 .86.96
X = 125, = 24, n = 24, construct a 99% confidence interval estimate for the population mean, .
2.
112.38 137

BUS 229 CP 28 Problems
Multiple Regression Models
1.
A mail-order catalog business that sells personal computer supplies, software, and hardware
maintains a centralized warehouse for the distribution of products ordered. Management is currently
examining

229 CP 7
1.
Below are two distributions interruptions per day in two large computer networks (A and B).
1. Compute the expected value for each distribution
Network A
Standard
Deviation
# Interruptions
P(X=x)
0
0.5
0
1
0.2
0.2
2
0.15
0.3
3
0.1
0.1
4
0.05
0

229 CP 20 Problems
Two Sample Tests and Comparing the Means of Two Independent Samples
1.
Assume that you have a sample of n1 = 8, with the sample mean X1 = 42, and a sample standard
deviation S1 = 4, and you have an independent sample of n2 = 15 from ano

229 CP 17 Problems
Hypothesis Testing with the t test
1.
If the sample of n = 16 selected from a normal population,
tstat if you are testing null Hypothesis H0 : =50 ? 2
X
= 56 and S = 12, what is the value of
2.
In problem 1, what are the critical values

229 CP 11
Sampling Distributions
A.
B.
C.
D.
1. Given a distribution of with =100 and =10 , if you select a sample of n = 25, what is the probability
that the sample X is
less than 95? 0.006
between 95 and 97.5? 0.10565
above 102.2? 0.13567
There is a 65%

229 CP 15
Confidence Interval Estimates and Determining Sample Size
1. A manufacturing company produces electric insulators for power lines. If the insulators break while in use,
a short circuit is likely to occur. To test the strength of the insulators,

White (dummy 0)
Red (dummy 1)
.93 + .47*alcohol
(.93 - .26) + .47*alcohol
*REMEMBER: "that predicts _" means that factor is the y-variable!*
This is found using regression analysis.
B.
Interpret the regression coefficients.
Intercept: Pointless to interpr

A. 1. Ho: There is no relationship between x and y.
Ha: There is a relationship between x and y.
Observed
Yes
No
Total
Northeast
Expected
Yes
No
Total
Northeast
102
74
176
2. Significance Level: = .05
3. Test Statistic:
^2 = [(fo - fe)^2/fe]
4. Decision R

Sampling Distributions
Sampling Distributions
When sampling, the resulting sample
statistics or point estimates are random
variables
Like any random variable, they have some
probability distribution
The probability distribution for a sample
statistic is

Measures of Dispersion
Measures of Dispersion
Measures the variability in the data
Common measures of dispersion are the
range, interquartile range, variance,
standard deviation, and the coefficient of
variation
Range
The range measures
the overall sprea

BUS 229
Measures of Central Tendency
Measures of Central Tendency
Mean: The average of the numbers in a data
set
Median: The center value in the data set
(once the data has been ordered from
smallest to largest)
Mode: The observation that occurs most
fr

Confidence Interval for a
Population Proportion
CI for p
The CI for is centered on the point estimate
A z value is always used, since the normal
approximation to the binomial is being used
An estimate of the standard error must be used
since p is unknown

Probability Distributions for
Continuous Random Variables
Continuous Distributions
Continuous Probability distributions can be
represented either graphically or by
mathematical function
Since there are an infinity of possible
values for the random variab

Confidence Intervals
Interval Estimates
An interval estimate is a span of values that
should include an unknown parameter
value. It is defined by two endpoints
Confidence
Confidence is a number between 0 and 100
that reflects the probability (x100%) that

Descriptive Statistics
Descriptive Statistics
Descriptive (Summary) statistics are ways
of summarizing the data
Types of Summary
frequency distributions
graphs
central tendency
dispersion
association
Frequency Distributions
Frequency Distributions are ta

BIA 229 CP 5
1.
What is the preferred way to order fast food? A survey conducted in 2009 but the sample sizes were not
reported. Suppose the results based on the sample of 100 males and 100 females, were as follows:
If a respondent is selected at random,

229 CP 6 Problems
1.
While tablets sales has slowed according to a recent report by IDC, there is still strong interest in using
them to consume entertainment.
http:/www.computerworld.com/s/article/9248653/IDC_drops_tablet_sales_forecast_sees_phablets_enc

229 CP 8
1.
Given the probability distribution for two funds X and Y in the table below:
Compute the
a.
E(X) 140 and E(Y) 160
of x of y SD(X)= 48.98979 SD(Y)= 48.98979
b.
of xy -2400
c.
d.
E(X+Y) 300
2.
You are trying to develop a strategy for investing

229 CP 9
Normal Distributions and Probabilities
1.
Given a normal distribution with =100
A.
X > 75? 0.9938
B.
X < 70? 0.0013
C.
X < 80 or X > 110? 0.8186
2.
In 2011, the per capita consumption of coffee in the United States was reported to be 4.16 kg or 9

229 CP 14 Problems
Confidence Interval Estimation
If X = 75, S = 24, and n = 36, and assuming that the population is normally distributed, construct a
1.
95% confidence interval estimate for the population mean, .
66.88 83.12
2. Assuming that the populati

229 CP 12 Problems
Sampling Distribution of the Proportion
1. In a random sample of 64 people, 48 are classified as successful.
a. Determine the sample proportion, p of successful people. 0.75
b. If the population proportion is 70, determine the standard

CP 10
Evaluating Normality
Include screenshots of your graphical and tabular analysis in this word document and upload at the end of
class.
1.
The file SUV.xls contains the overall miles per gallon (MPG) of 2012 small SUVs (n=18). Download this
file from

229 CP 18 Problems
Hypothesis Testing and One Tailed Tests
1.
2.
3.
4.
5.
6.
A.
B.
C.
D.
In a one-tailed hypothesis test where you reject H0 only in the upper tail, what is the p-value if Zstat =
+2.00?
0.0228
In problem 1, what is your statistical decisi

229 CP 19 Problems
Z Test of Hypothesis for the Proportion
1.
If, in a random sample of 400 items, 88 are defective, what is the sample proportion of defective items?
0.22
2.
In problem 2, if the null hypothesis is that 20% of the items in a population ar

229 CP 22 Problems
Comparing the Proportions of Two Independent Populations
1.
2.
Let n1 = 100, X1 = 50, n2 = 100, and X2 = 30.
A.
At the the 0.05 level significance, is there evidence of a significant difference between the two
population proportions? Ye