Probability
Hypothesis Testing
Regression
Formulas
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
On the midterm: never
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
What is the formula for the mean of X?
x̄ = ( Σ xi ) / n
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
What two factors define experiments?
Validity. Application: the ability to randomize
Power. Application: control of the independent variable
200
What does a B0 of -2.34 mean?
When the x variable is equal to 0, the projected value of the independent variable is -2.34.
200
Calculate a regression by hand.
Jk free points for you IF you can tell me where to find how to do this on Learning Suite.
Under the key for PS 6
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
When do I calculate a T-score and when do I calculate a Z-score?
Z when population standard deviation is known and T when the population standard deviation is not known and/or the N-size is very small (less than 30).
According to Dr. Barber, generally default to T-statistic.
300
What is SSR?
SSR is the Sum of the Squared Residuals. It is the sum of the difference between the predicted values and the actual values according to our regression model. It tells us approximately how far away predicted values are from actual, observed values.
300
Write a formula for a regression.
y= Bo + B1x + ... + E
300
How did Dr. Busby meet his wife?
Helping her move in at graduate school
400
What is the formula for Bayes Theorem?
Pr 𝐴|𝐵 = Pr(𝐵|𝐴)∗Pr(𝐴) Pr(𝐵)
400
What does a 95 confidence interval tell us?
We are 95% confident that he true population value of a statistic falls within this range.
400
Interpret B0, B1, and R-Squared from this regression output:
B0: The predicted salary of an NBA player who makes 0 points is 1,677,561.9$
B1: For each point an NBA player makes, their associated salary increases by 10,232.5$
R-squared: Points accounts for 37.37% of the variation in salary.
400
What is the formula for a two sample ttest?
400
Where did Dr. Busby serve his mission?
Indiana
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
WITHOUT using a p-value calculator, does this T-score indicate that we should reject the null hypothesis of no difference between the two variables?
5.782
Yes. That is a very large T-score
500
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
500
WITHOUT the internet, what is the formula for a 95% confidence interval using a Z critical value?
Where Z= 1.95996
500
Dr. Busby's most recently listed publication is titled:
(will accept any of the key words as an answer)
NO INTERNET ALLOWED
Framing and Blame Attribution in Populist Rhetoric