Probability
Hypothesis Testing
Regression
Advanced Regression
Dr. Busby Fun Facts
100
What is the addition rule?
Pr (A or B) = Pr(A) + Pr(B) – Pr(A and B)
If A and B are disjoint, this becomes: Pr (A or B) = Pr(A) + Pr(B)
100
When do we use a chi-squared test?
When we are trying to see the relationship between one or two categorical variables
100
What does R-squared tell us?
What percent of the variation in Y can be explained by the independent variables we have included
100
When do I use a squared term?
If the relationship between X and Y looks parabolic
100
Where did Dr. Busby get his PhD
Northwestern
200
What is the multiplication rule?
Pr(A and B) = Pr(A|B)*Pr(B)
If the events are independent: Pr(A and B) = Pr(A) * Pr(B)
200
When can we assume that something has strong internal validity?
If it meets the causal criteria (empirically connected, no inverse correlation, no confounders)
200
What does (E)=0 mean
There is constant variance of the error terms, meaning that we assume that our model is homoskedastic
200
What 2 things do I need to do in order to make a regression account for panel data in stata?
1. i.variable
2. clustered standard errors- , cluster(variable)
200
How many of Dr. Busby's brothers are bald?
None
300
What is the formula for conditional probability?
Pr 𝐴|𝐵 = Pr(𝐴∩𝐵) 𝑃(𝐵)
300
What is the formula for a proportions test?
(𝑝1 − 𝑝2)/ sqrt (𝑝𝑡𝑜𝑡𝑎𝑙 ∙ (1 − 𝑝𝑡𝑜𝑡𝑎𝑙)) ∗ ( 1/𝑛1 + 1/𝑛2 )
300
Write a formula for a regression with controls on the board
y= Bo + B1x + B2w + B3z +... + E
300
Write down the equation for an interaction on the board
y= B0 + B1(x) + B2(w) + B3(x*w)
300
Where did Dr. Busby serve his mission?
Indiana, Indianapolis: Spanish Speaking
400
What is the formula for Bayes Theorem?
Pr 𝐴|𝐵 = Pr(𝐵|𝐴)∗Pr(𝐴) Pr(𝐵)
400
What is the formula for a ttest?
400
What is SER/ Root MSE
Root Mean Squared Error (Root MSE) is the standard deviation of the residuals. It shows us how tightly fit the data is to our regression line
400
How do I interpret a log-log equation?
In log log, the beta one remains the same, but both variables turn into percents
(i.e. a 1% change in x results in a B1% change in y)
400
How did Dr. Busby meet his wife?
He helped her move in (specifically helped her move her couch in)
500
Construct a probability tree for the following scenario:
Jimothy flips a coin three times. He has a 30% chance of flipping heads and a 70% chance of flipping tails. What is the probability that he will flip heads only once?
Congrats! You made the tree!
500
Yay free points for you!
No strings attached I'm just lazy
500
Interpret this Stata output:
You did it! Yay!
500
Interpret the following equation in an interaction model:
Health= 3.7 + 1.2 (medicine) + 5 (grapefruit) - 57000 (medicine * grapefruit)
3.7 is the expected health score of someone who does not take medicine or eat any grapefruits
When a person eats 0 grapefruits a week, taking medicine increases their health score by 1.2 points
When a person does not take medicine, each additional grapefruit they eat increases their health score by 5 points
When a person does take medicine, each additional grapefruit decreases their health score by an additional 57000 points (added to 5* number of grapefruits)
500
Dr. Busby's most recently listed publication is titled:
(will accept any of the key words as an answer)
Framing and Blame Attribution in Populist Rhetoric