chapter 1 Flashcards
1
Q
regression lines are used to model which relatinoship?
A
LINEAR
2
Q
y = ax^n
A
log y = log a + nlogx
3
Q
y = ab^x
A
log y = log a + x log b
EXPONENTIAL
4
Q
PREDICTIONs outside of data range
A
extrapolation
5
Q
PMCC
A
- product moment correlation coefficient (r)
- describes the linear correlation between 2 variables
- STRENGTH and TYPE of correlation
- -1 to 1
6
Q
-1 PMCC
A
perfect negative linear correlation (straight line)
7
Q
1 PMCC
A
perfect positive linear correlation (straight line)
8
Q
use PMCC to comment on suitability of a linear regression model
A
- if PMCC close to 1 or -1, suitable
- data points lie close to a straight line
9
Q
reject H0 if…
A
observed value is WITHIN ciritcal region
10
Q
‘evidence of correlation’
A
use a TWO tailed test
split the significance level
11
Q
H0 is ALWAYS
A
p = 0 (no correlation)
12
Q
critical value when p/= 0
A
+- formula book value
13
Q
if critical value > observed
A
NO EVIDENCE OF CORRELATION
14
Q
what IS the significance level
A
propability that null hypothesis (h0) is true
