Essentials of Statistics for The Behavioral Sciences (MindTap Course List)
9th Edition
ISBN: 9781337098120
Author: Frederick J Gravetter, Larry B. Wallnau, Lori-Ann B. Forzano
Publisher: Cengage Learning
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Chapter 15, Problem 7P
Automobile insurance is much more expensive for teenage drivers than for older drivers. To justify this cost difference, insurance companies claim that the younger drivers are much more likely to be involved in costly accidents. To test this claim, a researcher obtains information about registered drivers from the department of motor vehicles and selects a sample of n = 300 accident reports from the police department. The motor vehicle department reports the percentage of registered drivers in each age category’ as follows; 16% are younger than age 20; 28% are 20 to 29 years old; and 56% are age 30 or older. The number of accident reports for each age group is as follows:
- a. Do the data indicate that the distribution of accidents for the three age groups is significantly different from the distribution of drivers? Test with α = .05.
- b. Compute Cohen’s w to measure the size of the effect
- c. Write a sentence demonstrating how the outcome of the hypothesis test and the measure of effect size would appear in a research report.
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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).
A well-known company predominantly makes flat pack furniture for students. Variability with the automated machinery means the wood components are cut with a standard deviation in length of 0.45 mm. After they are cut the components are measured. If their length is more than 1.2 mm from the required length, the components are rejected.
a) Calculate the percentage of components that get rejected.
b) In a manufacturing run of 1000 units, how many are expected to be rejected?
c) The company wishes to install more accurate equipment in order to reduce the rejection rate by one-half, using the same ±1.2mm rejection criterion. Calculate the maximum acceptable standard deviation of the new process.
Chapter 15 Solutions
Essentials of Statistics for The Behavioral Sciences (MindTap Course List)
Ch. 15.1 - Which of the following is a characteristic of...Ch. 15.1 - Which of the following accurately describes the...Ch. 15.1 - A researcher uses a sample of n = 60 participants...Ch. 15.2 - Prob. 1LCCh. 15.2 - Prob. 2LCCh. 15.2 - A researcher uses a sample of 20 college...Ch. 15.3 - If a chi-square test for independence has df 3,...Ch. 15.3 - Prob. 2LCCh. 15.3 - Prob. 3LCCh. 15.4 - Prob. 1LC
Ch. 15.4 - A researcher obtains X2 = 4.0 for a test for...Ch. 15.4 - Under what circumstances should the chi-square...Ch. 15.5 - Prob. 1LCCh. 15.5 - Prob. 2LCCh. 15 - Prob. 1PCh. 15 - The student population at the state college...Ch. 15 - A developmental psychologist would like to deter...Ch. 15 - Data from the Department of Motor Vehicles...Ch. 15 - A psychologist examining art appreciation selected...Ch. 15 - A professor in the psychology department would...Ch. 15 - Automobile insurance is much more expensive for...Ch. 15 - A communications company has developed three new...Ch. 15 - Prob. 9PCh. 15 - Earlier in the chapter, we introduced the...Ch. 15 - Liu el al. (2015) recently reported the results of...Ch. 15 - Many businesses use some type of customer loyalty...Ch. 15 - In a classic study, Loftus and Palmer (1974)...Ch. 15 - In a study investigating freshman weight pain, the...Ch. 15 - Research results suggest that IQ scores for boys...Ch. 15 - Gender differences in dream content are well...Ch. 15 - Many parents allow their underage children to...Ch. 15 - A recent study indicates that people tend to...Ch. 15 - Research indicates that people who volunteer to...Ch. 15 - Research has demonstrated strong gender...
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