Correlation and Regression flashcards
15 practice cards drawn from the Correlation and Regression lessons. Tap a card to turn it over. Every answer is checked against the lesson it came from.
Read the Correlation and Regression lessons in full →
Which value of r fits these dots best?
0.05
from “Pearson’s Correlation Coefficient”
With n = 20 the critical value is 0.444, and r comes to 0.564. What follows?
reject : the correlation is real
from “Critical Values of r”
With n = 10 the critical value is 0.632, and r comes to 0.512. What follows?
do not reject : it could be chance
from “Critical Values of r”
Which total does the regression line of y on x make smallest?
the squared vertical gaps
from “The Least-Squares Regression Line”
Cost = 8n + 35 was fitted to n items. What is the 35?
the cost before any items are made
from “The Least-Squares Regression Line”
The fitted line is y = 0.5x + 1.5. Predict y when x is 3.
3
from “Predicting from a Regression Line”
The fitted line is y = 0.5x + 3. Predict y when x is 4.
5
from “Predicting from a Regression Line”
Two values tie for the places 2 and 3. What rank does each take?
2.5
from “Spearman’s Rank Correlation”
Ranked smallest first, what rank does the marked value get?
3
from “Spearman’s Rank Correlation”
Where do the line of y on x and the line of x on y always meet?
at the mean of x and the mean of y
from “The Regression Line of x on y”
You know a score and want the hours behind it. Which line?
x on y
from “The Regression Line of x on y”
The squared gaps to the mean total 25 and the squared gaps to the line total 4. What is R squared?
0.84
from “The Coefficient of Determination”
A model reports . What does that say?
81 percent of the variation in y is accounted for
from “The Coefficient of Determination”
Which quantity does least squares make smallest when it fits a curve?
the total of the squared vertical gaps
from “Non-Linear Regression”
Counts that double every two weeks are fitted best by which family?
exponential
from “Non-Linear Regression”