Learning Materials
Features
Discover
Chapter 12: Q. 12.98 (page 518)
If a variable of two populations has only two possible values, the chi-square homogeneity test is equivalent to a two-tailed test that we discussed in an earlier chapter. What test is that?
The test is two proportionsz-test
Over 30 million students worldwide already upgrade their learning with Vaia!
All the tools & learning materials you need for study success - in one app.
Get started for free
Ancestry and Region. The U.S. Census Bureau collects information on the U.S. population by ancestry and region of residenc and publishes the results in American Community Survey. Accordin; to that document, 18 % of the population resides in the Northeast.
a. If ancestry and region of residence are not associated, wha percentage of Americans of Irish ancestry would reside in the Northeast?
b. There are roughly 37 million Americans of Irish ancestry. If ancestry and region of residence are not associated, how many Americans of Irish ancestry would reside in the Northeast?
c. There are, in fact, 9.25 million Americans of Irish ancestry who reside in the Northeast. Given this information and your answer to part (b), what can you conclude?
Regarding the expected-frequency assumptions for a chi-square goodness-of-fit test, a chi-square independence test, or a chi-square homogeneity test,
a. state them.
b. how important are they?
A chi-square independence test is to be conducted to decide whether an association exists between two variables of a population. One variable has six possible values, and the other variable has four. What is the degrees of freedom for the statistic?
Table 12.4 on page 486 showed the calculated sums of the observed frequencies, the expected frequencies, and their differences. Strictly speaking, those sums are not needed. However, they serve as a check for computational errors.
a) In general, what common value should the sum of the observer frequencies and the sum of the expected frequencies equal? Ex plain your answer.
b) Fill in the blank. The sum of the differences between each observed and expected frequency should equal
c) Suppose that you are conducting a chi-square goodness-of-fit test. If the sum of the expected frequencies does not equal the sample size, what do you conclude?
d) Suppose that you are conducting a chi-square goodness-of-fit test. If the sum of the expected frequencies equals the sample size, can you conclude that you made no error in calculating the expected frequencies? Explain your answer.
Scoliosis is a condition involving curvature of the spine. In a study by A. Nachemson and L. Peterson, reported in the Journal of Bone and Joing Surgery, girls aged to years were followed to determine the effects of observation only (patients), an underarm plastic brace (patients), and nighttime surface electrical stimulation ( patients). A treatment was deemed to have failed if the curvature of the spine increased by 6 on two successive examinations. The following table summarizes the results obtained by the researchers.
At the significance level, do the data provide sufficient evidence to conclude that a difference in failure rate exists among the three types of treatments?
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Exams 
GCSE 
IGCSE 
AS 
A Level 
International A Level 
University Admissions Tests 
Flashcards 
Vaia AI 
Notes 
Study Plans 
Study Sets 
Find a job 
Find a degree 
Student Deals 
Magazine 
Mobile App