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1. Assume you are trying to determine whether hummingbirds prefer the feeder on

ID: 3318809 • Letter: 1

Question

1. Assume you are trying to determine whether hummingbirds prefer the feeder on the south side of your house or the feeder on the north side. For which of the following tests would a one-way (goodness of fit) chi-square test be appropriate?

testing whether the mean volume of nectar consumed from the north feeder in a day differs from the south feeder

testing whether the number of birds that visit the north feeder in one day differs from the number that visit the south feeder

testing whether there is a relationship between nectar type (sugar-water vs. store bought) and feeder location (north vs. south

testing whether the amount of time that each bird spends at the north feeder differs from the amount of time the same bird spends at the south feeder for all birds that visit both feeders

2. For which type of variables can the chi-square distribution be used to examine their relationship?

dependent only

independent only

continuous

"'categorical"

3. A researcher wanted to test the relationship between reaction time and time of day. She recruited 30 students and gave them a reaction time test in the morning and then the same test in the afternoon. The results of the test were classified as either "pass" or "fail". She found that in the morning 10 passed and 20 failed, and in the afternoon 15 passed and 15 failed. Can she use a chi square test of independence to see if there is a relationship between test performance and the time of day?

yes, because the chi-square test of independence can be used to determine the significance level

no, it would not be appropriate to use a chi square test of independence because there are only two levels of each variable in this example

no, it would not be appropriate to use a chi square test of independence because each subject contributed data to more than one cell

yes, because the chi square test of independence can be used to test deviations between theoretically expected and observed frequencies

testing whether the mean volume of nectar consumed from the north feeder in a day differs from the south feeder

testing whether the number of birds that visit the north feeder in one day differs from the number that visit the south feeder

testing whether there is a relationship between nectar type (sugar-water vs. store bought) and feeder location (north vs. south

testing whether the amount of time that each bird spends at the north feeder differs from the amount of time the same bird spends at the south feeder for all birds that visit both feeders

2. For which type of variables can the chi-square distribution be used to examine their relationship?

dependent only

independent only

continuous

"'categorical"

3. A researcher wanted to test the relationship between reaction time and time of day. She recruited 30 students and gave them a reaction time test in the morning and then the same test in the afternoon. The results of the test were classified as either "pass" or "fail". She found that in the morning 10 passed and 20 failed, and in the afternoon 15 passed and 15 failed. Can she use a chi square test of independence to see if there is a relationship between test performance and the time of day?

Answers:

yes, because the chi-square test of independence can be used to determine the significance level

no, it would not be appropriate to use a chi square test of independence because there are only two levels of each variable in this example

no, it would not be appropriate to use a chi square test of independence because each subject contributed data to more than one cell

yes, because the chi square test of independence can be used to test deviations between theoretically expected and observed frequencies

Explanation / Answer

(1) In a goodness of fit we need to observe how many birds vist the north side and south side and then test if the expected frequencies (which are equally likely) differ from the Observed.

Therefore---testing whether the number of birds that visit the north feeder in one day differs from the number that visit the south feeder

(2) Chi square is used for categorical variables.

(3) yes, because the chi square test of independence can be used to test deviations between theoretically expected and observed frequencies