Chi Square Set-Up and Conditions
Chi Square Calculations
Chi Square Conclusions
Inference for Slopes
Potpourri
Summer Trivia
100
We want to determine whether or not musical preference among high school students has any influence on these students' preference of social media sites.
We would use a __________
Chi-Square Test for Association/Independence
100
__________ determines the number of Degrees of Freedom for a Chi-Square Test for Association/Independence.
(# of rows - 1)*(# of columns - 1)
100
At the alpha=0.01 significance level, a Chi-Square statistic of 30 and a df of 15 would result in the following conclusion.
We do not have sufficient to reject the null hypothesis. We must fail to reject.
100
What proportion of the variation in electricity production is explained by its linear relationship with wind velocity?
87.3%
100
The larger the Chi-Square statistic, the __________ the p-value.
Smaller
100
Two vegetables experience higher sales in August than during all the other months of the year in the US. Name one of the vegetables.
Corn and squash
200
Conditions necessary for a chi-squared test for independence include which of the following?
1. Two independent random samples.
2. Expected counts to be greater than 10.
3. np and n(1-p) must both be greater than 5.
None of those are necessary
200
The formula for calculating the expected counts of a Chi-Square Test for Homogeneity is __________.
[(Row Total)*(Column Total)]/(Table Total)
200
We are testing whether or not the city of Lisle has the same age distribution as that of Downers Grove. Our Chi-Square value is 17.8, and our p-value is 0.003. A complete conclusion (based on a significance level of alpha=0.05) is __________.
Since our p-value (0.003) is less than our significance level of alpha=0.05, we must reject the null hypothesis. We do have sufficient evidence to suggest that there IS a difference between the distribution of age among Lisle residents and the distribution of age among DG residents.
200
t = (stat - null)/SE = (14.686 - 0)/13.329 = 1.1
200
A Chi-Square Test for Homogeneity is used when we want to compare __________ with __________.
the distribution of one categorical variable for one sample
the distribution of the same categorical variable for a second sample
200
What vitamin can you get from direct sunlight?
Vitamin D
300
We want to see if hand dominance (being right-handed or left-handed) and eye color are genetically linked.
The hypotheses for this test would be __________.
Ho: There is no association between hand dominance and eye color.
Ha: There is an association between hand dominance and eye color.
300
The formula for calculating a Chi-Square Test Statistic is __________.
The sum of [(observed - expected)^2]/(expected)
300
We ran a Chi-Square test to determine whether juniors or seniors traditionally score higher on their AP Statistics exams. We got a Chi-Square statistic of 3.72 and a p-value of 0.146. A complete conclusion (based on a significance level of alpha=0.05) is __________.
Since our p-value (0.146) is greater than our significance level of alpha=0.05, we must fail to reject the null hypothesis. We do NOT have sufficient evidence to suggest that there is a difference between the distribution of AP Statistics exam scores for juniors and the distribution of AP Statistics exam scores for seniors.
300
-1.133 +- 2.365(.27) = (-1.77, -0.49)
300
The distinction between a Chi-Square Test for Homogeneity and a Chi-Square GOF Test is ...
Two-Samples vs One-Sample
300
The month of July was named after which historical personality?
Julius Caesar
400
We want to know if People from Georgia and New York prefer the same brand of toothpaste, so we will take a sample of residents from each state and record the number of individuals who prefer each brand of toothpaste.
The hypotheses for this test would be __________.
Ho: There is no difference between the distribution of toothpaste preference for residents of Georgia and the distribution of toothpaste preference for residents of New York.
Ha: There is a difference between the distributions of toothpaste preference between the two states.
400
We calculate the expected counts in a Chi-Square GOF Test by _________.
multiplying the sample size by the respective proportion
400
We want to determine whether or not musical preference among high school students has any influence on these students' preference of social media sites. The Chi-Square statistic was 18.7 and the df was 10. Give a complete conclusion.
Since our p-value (0.044) is less than our significance level of alpha=0.05, we must reject the null hypothesis. We have sufficient evidence to conclude that there IS an association between musical preference and social media site preference.
400
Is there statistically convincing evidence that electricity production by the windmill is related to wind velocity? Explain.
Yes, the p-value = 0, which gives us evidence to reject the null and support the alternate hypothesis that wind velocity does have an effect on wind production.
400
When would we want to conduct a Follow-Up Analysis?
When we make a decision to reject the null hypothesis
400
Which summer blockbuster film was the first to be promoted to the audience by expensive television advertising?
Jaws