IDS 270 Exam 1 Questions with Verified
Correct Answers
What is the formula for finding residuals?
y-yhat=residual
When do you know a residual graph is over predicting?
When the point on the residual graph is below the x-axis, meaning that it's negative.
When do you know a residual graph is under predicting?
When the point on the residual graph is above the x-axis, meaning it is a positive number
How do you know a relationship between x & y is positive?
If the slope is positive, the graph is positive, so that means it's a positive relationship between
x&y
How can you characterize the strength of the relationship between x & y?
By calculating (r)^2. The closer r^2 is to 1, the stronger the relationship is.
If x increases by 1, what is the predication for the change in y?
The change in y is dependent on the amount of regression.
If you: roll even on a red die, and roll an odd on a green die, these are __________
independent
If you: roll an even on red and roll an odd on red, these are ____
disjoint
Formula for the union of two probabilities?
, Pr(A U B)= P(a) + P(b) - Pr(A and B)
Formula for: Pr(A and B)?
P(a) * P(b)
How do you know if two parts to a probability problem are independent of each other?
If Pr(A and B) = P(a) * P(b) = Pr(A and B)
Population Distribution
Entire Population being used
Sample distribution
Initial samples taken from population distribution
Sampling distribution
Averages from all samples taken
What shape is related to Central Limit Theorem?
Bell shape
Finding the Standard Deviation based on C.L.T
S.D of population / Root( # in each sample
If you compare two spreads, which number will be a tighter spread, big or small
number?
Smaller number
What method do you use in order to get: What % of test takers can expect 700 or less
Correct Answers
What is the formula for finding residuals?
y-yhat=residual
When do you know a residual graph is over predicting?
When the point on the residual graph is below the x-axis, meaning that it's negative.
When do you know a residual graph is under predicting?
When the point on the residual graph is above the x-axis, meaning it is a positive number
How do you know a relationship between x & y is positive?
If the slope is positive, the graph is positive, so that means it's a positive relationship between
x&y
How can you characterize the strength of the relationship between x & y?
By calculating (r)^2. The closer r^2 is to 1, the stronger the relationship is.
If x increases by 1, what is the predication for the change in y?
The change in y is dependent on the amount of regression.
If you: roll even on a red die, and roll an odd on a green die, these are __________
independent
If you: roll an even on red and roll an odd on red, these are ____
disjoint
Formula for the union of two probabilities?
, Pr(A U B)= P(a) + P(b) - Pr(A and B)
Formula for: Pr(A and B)?
P(a) * P(b)
How do you know if two parts to a probability problem are independent of each other?
If Pr(A and B) = P(a) * P(b) = Pr(A and B)
Population Distribution
Entire Population being used
Sample distribution
Initial samples taken from population distribution
Sampling distribution
Averages from all samples taken
What shape is related to Central Limit Theorem?
Bell shape
Finding the Standard Deviation based on C.L.T
S.D of population / Root( # in each sample
If you compare two spreads, which number will be a tighter spread, big or small
number?
Smaller number
What method do you use in order to get: What % of test takers can expect 700 or less
