Question 1

In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true,

Accepted Answer

A)  a Type I error has been committed 
B)  a Type II error has been committed 
C)  either a Type I or Type II error has been committed 
D)  the correct decision has been made 
A)  a Type I error has been committed 
B)  a Type II error has been committed 
C)  either a Type I or Type II error has been committed 
D)  the correct decision has been made

Question 2

Exhibit 9-7
A random sample of 16 statistics examinations from a large population was taken. The average score in the sample was 78.6 with a variance of 64. We are interested in determining whether the average grade of the population is significantly more than 75. Assume the distribution of the population of grades is normal.
-Refer to Exhibit 9-7. The test statistic is

Accepted Answer

A)  0.45 
B)  1.80 
C)  3.6 
D)  8 
A)  0.45 
B)  1.80 
C)  3.6 
D)  8

Question 3

For a one-tailed test lower tail) at 93.7% confidence, Z =

Accepted Answer

A)  -1.86 
B)  -1.53 
C)  -1.96 
D)  -1.645 
A)  -1.86 
B)  -1.53 
C)  -1.96 
D)  -1.645

Question 4

In the past, the average age of employees of a large corporation has been 40 years. Recently, the company has been hiring older individuals. In order to determine whether there has been an increase in the average age of all the employees, a sample of 64 employees was selected. The average age in the sample was 45 years with a standard deviation of 16 years. Let α = .05.
a. State the null and the alternative hypotheses.
b. Compute the test statistic.
c. Using the p-value approach, test to determine whether or not the mean age of all employees is significantly more than 40 years.

Accepted Answer

a. Ho: μ ≤ 40
Ha: μ

Question 5

The p-value ranges between

Accepted Answer

A)  zero and infinity 
B)  minus infinity to plus infinity 
C)  zero to one 
D)  -1 to +1 
A)  zero and infinity 
B)  minus infinity to plus infinity 
C)  zero to one 
D)  -1 to +1

Question 6

Consider the following hypotheses test.
Ho: μ ≥ 80 Ha: μ < 80
A sample of 121 provided a sample mean of 77.3. The population standard deviation is known to be 16.5.
a. Compute the value of the test statistic.
b. Determine the p-value; and at 93.7% confidence, test the above hypotheses.
c. Using the critical value approach at 93.7% confidence, test the hypotheses.

Accepted Answer

a. Z = -1.8
b. p-value = 0.035

Question 7

The level of significance

Accepted Answer

A)  can be any positive value 
B)  can be any value 
C)  is 1 - confidence level) 
D)  can be any value between -1.96 to 1.96 
A)  can be any positive value 
B)  can be any value 
C)  is 1 - confidence level) 
D)  can be any value between -1.96 to 1.96

Question 8

A sample of 81 account balances of a credit company showed an average balance of $1,200 with a standard deviation of $126.
a. Formulate the hypotheses that can be used to determine whether the mean of all account balances is significantly different from $1,150.
b. Compute the test statistic.
c. Using the p-value approach, what is your conclusion? Let α = .05.

Accepted Answer

a. Ho: μ = 1150
Ha:

Question 9

For a one-tailed test upper tail), a sample size of 26 at 90% confidence, t =

Accepted Answer

A)  1.316 
B)  -1.316 
C)  -1.740 
D)  1.740 
A)  1.316 
B)  -1.316 
C)  -1.740 
D)  1.740

Question 10

Exhibit 9-1
 $$\begin{array} { l l l l } 
\mathrm { n } = 36 & \bar { x } = 24.6 & \mathrm {~S} = 12 & \mathrm { H } _ { 0 } : \mu \leq 20 \
&& & \mathrm { H } _ { \mathrm { a } } : \mu > 20
\end{array}$$
-Refer to Exhibit 9-1. The p-value is between

Accepted Answer

A)  0.005 to 0.01 
B)  0.01 to 0.025 
C)  0.025 to 0.05 
D)  0.05 to 0.10 
A)  0.005 to 0.01 
B)  0.01 to 0.025 
C)  0.025 to 0.05 
D)  0.05 to 0.10

Question 11

Consider the following hypothesis test:
Ho: μ = 10
Ha: μ ≠ 10
A sample of 81 provides a sample mean of 9.5 and a sample standard deviation of 1.8.
a. Determine the standard error of the mean.
b. Compute the value of the test statistic.
c. Determine the p-value; and at 95% confidence, test the above hypotheses.

Accepted Answer

a. 0.2
b. t = -2.5
c

Question 12

Consider the following hypothesis test:
Ho: μ ≥ 40
Ha: μ < 40
A sample of 49 provides a sample mean of 38 and a sample standard deviation of 7.
a. Determine the standard error of the mean.
b. Compute the value of the test statistic.
c. Determine the p-value; and at 95% confidence, test the above hypotheses.

Accepted Answer

a. 1
b. t = -2
c. p-

Question 13

The average starting salary of students who graduated from colleges of Business in 2009 was $48,400. A sample of 100 graduates of 2010 showed an average starting salary of $50,000. Assume the standard deviation of the population is known to be $8,000. We want to determine whether or not there has been a significant increase in the starting salaries.
a. State the null and alternative hypotheses to be tested.
b. Compute the test statistic.
c. The null hypothesis is to be tested at 95% confidence. Determine the critical value for this test.
d. What do you conclude?
e. Compute the p-value.

Accepted Answer

a. Ho: μ ≤ 48,400
Ha : μ > 48,

In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true,

For a one-tailed test lower tail) at 93.7% confidence, Z =

The p-value ranges between

The level of significance

For a one-tailed test upper tail), a sample size of 26 at 90% confidence, t =

Exhibit 9-1 =36 =24.6 =12 :\mu\leq20 :\mu>20 -Refer to Exhibit 9-1. The p-value is between

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Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

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Exam 9: Hypothesis Tests

In hypothesis testing if the null hypothesis has been rejected when the alternative hypothesis has been true,

For a one-tailed test lower tail) at 93.7% confidence, Z =

The p-value ranges between

The level of significance

For a one-tailed test upper tail), a sample size of 26 at 90% confidence, t =

Exhibit 9-1 =36 =24.6 =12 :\mu\leq20 :\mu>20 -Refer to Exhibit 9-1. The p-value is between

Data and Statistics

Descriptive Statistics: Tabular and Graphical Displays

Descriptive Statistics: Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling and Sampling Distributions

Interval Estimation

Comparisons Involving Means, Experimental Design, and Analysis of Variance

Comparisons Involving Proportions and a Test of Independence

Simple Linear Regression

Multiple Regression

Filters