Set-Up and Conditions
Calculations
Conclusions
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
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. Our sample must be larger than 30.
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
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 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.
300
t = (stat - null)/SE = (14.686 - 0)/13.329 = 1.1
300
Is there statistically convincing evidence that electricity production by the windmill is related to wind velocity? Explain.
Yes, the test statistic is 12.63 and the p-value = 0 (no need to divide by 2 for this two sided test), which gives us evidence to reject the null and support the alternate hypothesis that wind velocity does have an effect on wind production.
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
Based on the plots below which of the 5 conditions for slope inference would fail?
Linear Fails The residual plot shows a clear curve.
Independence Cannot be determined from plots
Normal Passes There is no strong skew or outliers in the dotplot of residuals
Equal Variance Fails the residuals get larger as the x-values increase.
Random Cannot be determined from plots
400
-1.133 +- 2.365(.27) = (-1.77, -0.49)
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
The critical value used for creating intervals for means and slopes are mostly the same except for this distinct difference. What is that difference?
The degrees of freedom for means is n-1 while slopes use n-2
400
Which summer blockbuster film was the first to be promoted to the audience by expensive television advertising?
Jaws