EBK ESSENTIALS OF STATISTICS FOR BUSINE
8th Edition
ISBN: 8220103648783
Author: Anderson
Publisher: CENGAGE L
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Textbook Question
Chapter 12.1, Problem 6E
Error Rates in Tax Preparation. A tax preparation firm is interested in comparing the quality of work at two of its regional offices. The observed frequencies showing the number of sampled returns with errors and the number of sampled returns that were correct are as follows.
- a. What are the sample proportions of returns with errors at the two offices?
- b. Use the chi-square test procedure to see if there is a significant difference between the population proportion of error rates for the two offices. Test the null hypothesis H0: p1 = p2 with a .10 level of significance. What is the p-value and what is your conclusion? Note: We generally use the chi-square test of equal proportions when there are three or more populations, but this example shows that the same chi-square test can be used for testing equal proportions with two populations.
- c. In the Section 10.2, a z test was used to conduct the above test. Either a χ2 test statistic or a z test statistic may be used to test the hypothesis. However, when we want to make inferences about the proportions for two populations, we generally prefer the z test statistic procedure. Refer to the Notes and Comments at the end of this section and comment on why the z test statistic provides the user with more options for inferences about the proportions of two populations.
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Worksheet 10
Jesse runs a small business selling and delivering mealie meal to the spaza shops.
He charges a fixed rate of R80, 00 for delivery and then R15, 50 for each packet of
mealle meal he delivers. The table below helps him to calculate what to charge
his customers.
10
20
30
40
50
Packets of mealie
meal (m)
Total costs in Rands
80
235
390
545
700
855
(c)
10.1.
Define the following terms:
10.1.1. Independent Variables
10.1.2. Dependent Variables
10.2.
10.3.
10.4.
10.5.
Determine the independent and dependent variables.
Are the variables in this scenario discrete or continuous values? Explain
What shape do you expect the graph to be? Why?
Draw a graph on the graph provided to represent the information in the
table above.
TOTAL COST OF PACKETS OF MEALIE MEAL
900
800
700
600
COST (R)
500
400
300
200
100
0
10
20
30
40
60
NUMBER OF PACKETS OF MEALIE MEAL
Let X be a random variable with support SX = {−3, 0.5, 3, −2.5, 3.5}. Part ofits probability mass function (PMF) is given bypX(−3) = 0.15, pX(−2.5) = 0.3, pX(3) = 0.2, pX(3.5) = 0.15.(a) Find pX(0.5).(b) Find the cumulative distribution function (CDF), FX(x), of X.1(c) Sketch the graph of FX(x).
Chapter 12 Solutions
EBK ESSENTIALS OF STATISTICS FOR BUSINE
Ch. 12.1 - Use the sample data below to test the...Ch. 12.1 - reconsider the observed frequencies in exercise 1...Ch. 12.1 - Late Flight Comparison Across Airlines. The sample...Ch. 12.1 - Electronic Component Supplier Quality Comparison....Ch. 12.1 - Prob. 5ECh. 12.1 - Error Rates in Tax Preparation. A tax preparation...Ch. 12.1 - Prob. 7ECh. 12.1 - Prob. 8ECh. 12.2 - The following table contains observed frequencies...Ch. 12.2 - The following table contains observed frequencies...
Ch. 12.2 - Airline Ticket Purchases for Domestic and...Ch. 12.2 - Hiring and Firing Plans at Private and Public...Ch. 12.2 - Prob. 13ECh. 12.2 - A vehicle quality survey asked new owners a...Ch. 12.2 - Prob. 15ECh. 12.2 - Academy Awards and Movie Fan Sentiment. The race...Ch. 12.2 - Amount of Sleep by Age Group. The National Sleep...Ch. 12.2 - Prob. 18ECh. 12.3 - Test the following hypotheses by using the 2...Ch. 12.3 - The following data are believed to have come from...Ch. 12.3 - Television Audiences Across Networks. During the...Ch. 12.3 - M&M Candy Colors. Mars, Inc. manufactures M&M’s,...Ch. 12.3 - Shareholder Scoreboard Ratings. The Wall Street...Ch. 12.3 - Traffic Accidents by Day of Week. The National...Ch. 12.3 - Prob. 25ECh. 12.3 - Prob. 26ECh. 12 - Prob. 27SECh. 12 - Prob. 28SECh. 12 - Prob. 29SECh. 12 - Pace-of-Life Preference By Gender. A Pew Research...Ch. 12 - Church Attendance by Age Group. The Barna Group...Ch. 12 - Ambulance Calls by Day of Week. An ambulance...Ch. 12 - 33. Based on sales over a six-month period, the...Ch. 12 - Prob. 34SECh. 12 - Testing If Daily Sales Obey a Binomial Probability...Ch. 12 - In a study conducted by Zogby International for...
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