chpt 14 review Flashcards
With simple linear regression how many variables do we use
1 dependent and 1 independent variable
in simple linear regression what doe we use to appropximate the realtionship
a straight line
what is the line type to calculate slope and intercept
see sheet
what is the formula for slope
see sheet
what is the formula for intercept
see sheet
what is the line type to use for calculating SST/SSR/SSE/ R2/ and rxy
see sheet
What is the formula for r 2 (coefficent of determination)
SSR/SST
what does the coefficient of determination tell us
% of variation that can be explained by the ….. the gregression equation?
WHat are some importing things about the coefficent of determination
- cannot be negative
2. larger values imply that the observations are more closely gropued around the lease squares line
what is the formula for rxy (correlation coefficent)
sqaure root of r2
what does correlation coefficent tell us
strength of association b/w x and y
values are b/w 1 and -1
- values are positive or negative dependent on the slop (is it positive or negative)
Testing for significance for simple linear regression what is the null and alternative hypothesis
Ho: B1 = 0
Ha: B1 does not equal 0
NOTE: two tailed test
What are the rules for a two tailed test for a t-test
if positive, double the p-value
When testing for significance for simple linear regression what kind of tests can we use
t- test and F- test
In simple linear regression when you reject the t-test or the F- test what can you conclude
Reject Ho: conclude that a statistically significant relationship exists
Do Not reject Ho: not significant, conclude that no statistical evidence a significant relationship exists
How do you calculate the t-test for simple linear regression
t= bi/ sbi
How do you calculate sbi
- MSE = sse/n-2
- s = square root of MSE
- sbi = s/ sqaure root of sum (xi-xbar) square
what are the degrees of freedom for t test in simple linear regression
n-2
What is the formula for the F test in simple linear regression and what is the d-f
MSR/MSE
df - is what the df is for MSR and MSE
MSR df =
MSE df =
What is the confidence interval for simple linear regression
if 0 is included in the ibterval then …..
calculation: bi +/- ta/2sbi
in simple linear regression are the t-test and F-test provide the same result?
yes
For confidence and prediction intervals they are more precise when
the value of the independent value X* is closer to Xbar
which interval is wider confidence or prediction
prediction interval
What is the confidence interval used for
estimate of the MEAN value of Y for a given value of x
What is the prediction interval used for
used to predict the value of the dep. var y for a NEW observation
What do you use to MEASURE of how well the estimated regression line FITS the data
R2
Coefficient of Determination
What test do we use to test whether B1 is significant
t-test bi/sbi
