Question 1

Given the following information, calculate sp2, the pooled sample variance that should be used in the pooled-variance t test. 
$ \begin{array}{ll}s_{1}^{2}=4 & s_{2}^{2}=6 \ n_{1}=16 & n_{2}=25\end{array} $

Accepted Answer

A)  $ s \mathrm{p}^{2}=5.00 $ 
B)  $ s_{p}^{2}=4.00 $ 
C)  $ s_{p}^{2}=5.23 $ 
D)  $ s_{\mathrm{p}}{ }^{2}=6.00 $ 
A)  $ s \mathrm{p}^{2}=5.00 $ 
B)  $ s_{p}^{2}=4.00 $ 
C)  $ s_{p}^{2}=5.23 $ 
D)  $ s_{\mathrm{p}}{ }^{2}=6.00 $

Question 2

TABLE 10-8
 A buyer for a manufacturing plant suspects that his primary supplier of raw materials is overcharging. In order to determine if his suspicion is correct, he contacts a second supplier and asks for the prices on various identical materials. He wants to compare these prices with those of his primary supplier. The data collected is presented in the table below, with some summary statistics presented (all of these might not be necessary to answer the questions which follow). The buyer believes that the differences are normally distributed and will use this sample to perform an appropriate test at a level of significance of 0.01.
 $\begin{array}{crrr}
&\text { Primary}&\text { Secondary }\
\underline{\text {Material }}&\underline{\text {Supplier}}&\underline{\text { Supplier }}&\underline{\text {Difference }}\
1 & \$ 55 & \$ 45 & \$ 10 \
2 & \$ 48 & \$ 47 & \$ 1 \
3 & \$ 31 & \$ 32 & -\$ 1 \
4 & \$ 83 & \$ 77 & \$ 6 \
5 & \$ 37 & \$ 37 & \$ 0 \
6 & \$ 55 & \$ 54 & \$ 1 \
\hline \text { Sum: } & \$ 309 & \$ 292 & \$ 17\
\text { Sum of Squares: } &\$ 17,573& \$ 15,472 &\$ 139
\end{array}$

-Referring to Table 10-8, the p-value of the test is between ______and_____ .

Accepted Answer

The answer of TABLE 10-8
 A buyer for a manufacturing...

Question 3

If we are testing for the difference between the means of two related populations with samples of n1 = 20 and n2 = 20, the number of degrees of freedom is equal to

Accepted Answer

A)  38. 
B)  39. 
C)  18. 
D)  19. 
A)  38. 
B)  39. 
C)  18. 
D)  19.

Question 4

TABLE 10-11
A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course. The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course. The groups are assumed to be independent random samples. Let ×and × represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study, respectively.
-Referring to Table 10-11, what is the value of the test statistic to use in evaluating the alternative hypothesis that there is a difference in the two population proportions?

Accepted Answer

A)  0 
B)  4.335 
C)  1.96 
D)  1.093 
A)  0 
B)  4.335 
C)  1.96 
D)  1.093

Given the following information, calculate sp2, the pooled sample variance that should be used in the pooled-variance t test. =4 =6 =16 =25

If we are testing for the difference between the means of two related populations with samples of n₁= 20 and n₂= 20, the number of degrees of freedom is equal to

Introduction and Data Collection

Presenting Data in Tables and Charts

Numerical Descriptive Measures

Basic Probability

Some Important Discrete Probability Distributions

The Normal Distribution and Other Continuous Distributions

Sampling Distributions and Sampling

Confidence Interval Estimation

Fundamentals of Hypothesis Testing: One-Sample Tests

Analysis of Variance

Chi-Square Tests and Nonparametric Tests

Simple Linear Regression

Introduction to Multiple Regression

Multiple Regression Model Building

Time-Series Forecasting and Index Numbers

Decision Making

Statistical Applications in Quality Management

Statistical Analysis Scenarios and Distributions

Filters

Exam 10: Two-Sample Tests