Exam 25: Comparing Counts

At a high school debate tournament,half of the teams were asked to wear suits and ties and the rest were asked to wear jeans and t-shirts.The results are given in the table below.Is the proportion of wins the same for teams wearing suits as for teams wearing jeans? Use a 10% level of significance.

A publishing company performs sample surveys to obtain information on characteristics of book readers.A book reader is defined to be one who read one or more books in the six months prior to the survey;a non-book reader is defined to be one who read newspapers or magazines but no books in the six months prior to the survey;a nonreader is defined to be one who did not read a book,newspaper,or magazine in the six months prior to the survey.The following data were obtained from a random sample of 1429 persons 16 years old and over in an effort to determine whether or not the proportions of book readers,non-book readers,and non-readers are the same for each income bracket.

A car insurance company performed a study to determine whether an association exists between age and the frequency of car accidents.They obtained the following sample data. Does the data provide sufficient evidence to conclude that an association exists between age and frequency of car accidents? Use a 5% level of significance.

The two-way table summarizes data from the human resource department at a university: New Hires What is the probability (rounded to three decimal places)that a male new hire is tenure track?

What is the null hypothesis for the chi-square test of independence? What assumptions are required for this test?

A researcher performed a study to determine whether an association exists between gender and blood type.He obtained the following sample data. Does the data provide sufficient evidence to conclude that an association exists between gender and blood type? Use a 5% level of significance.

A researcher performed a study to determine whether an association exists between sex and blood type.He obtained the following sample data.

Suspecting that a die may be unfair,you want to investigate.To check,you roll it 36 times,recording the number of times each face appears. To see if these results are unusual,will you test goodness-of-fit,homogeneity,or independence?

A publishing company performs sample surveys to obtain information on characteristics of book readers.A book reader is defined to be one who read one or more books in the six months prior to the survey;a non-book reader is defined to be one who read newspapers or magazines but no books in the six months prior to the survey;a nonreader is defined to be one who did not read a book,newspaper,or magazine in the six months prior to the survey.The following data were obtained from a random sample of 1429 persons 16 years old and over in an effort to determine whether or not the proportions of book readers,non-book readers,and non-readers are the same for each income bracket.

A die,suspected of being unfair,was rolled 50 times.The number of times each face appeared was recorded in the following table.

A researcher performed a study to determine whether an association exists between political party affiliation and income.She obtained the following sample data. Does the data provide sufficient evidence to conclude that an association exists between political party affiliation and income? Use a 1% level of significance.

A researcher wishes to test the effectiveness of a flu vaccination.Fifty randomly selected people are vaccinated,80 randomly selected people are vaccinated with a placebo,and 300 randomly selected people are not vaccinated.The number in each group who later caught the flu was recorded.The results are shown below.

A car insurance company performed a study to determine whether an association exists between age and the frequency of car accidents.They obtained the following sample data.

You roll a die 48 times with the following results.Is the die fair?

Explain why a chi-square goodness-of-fit test is always right-tailed.

Use the sample data below to test whether car colour affects the likelihood of being in an accident.Use a 5% level of significance.

A researcher performed a study to determine whether political party affiliations are different for different income brackets.She obtained the following sample data.

In studying the responses to a multiple-choice test question,the following sample data were obtained.Are the responses uniformly distributed? Use a 10% level of significance.

Responses to a survey question are broken down according to employment status and the sample results are given below.Are the response and employment status independent? Use a 1% level of significance.

Describe a goodness-of-fit test.What assumptions are made when using a goodness-of-fit test?