Average X and Y
Coordinate
Variable Y
Negative Correlation
Variable X
Variable Y
No Correlation
Variable X
Positive Correlation
Variable X
Finding correlation coefficient
1)
(2nd) → (+)(plus sign) → (7)(seven) → (1)(one) → (2)(two)
TURN DIAGNOSTIC ON
2)
3)
4)
5)
YOU WILL PRESS (2nd) → (0)
SCROLL ALL THE WAY DOWN UNTIL YOU SEE DIAGNOSTIC ON
Press (enter)
YOU WILL PRESS (stat) → (edit)
A table should appear and you will enter your data into the L1 and L2. In this
situation cost will be implemented into L2 and years since 1978 into L1.
Part 2 correlation coefficient
6)
PRESS (stat) → arrow over to (calc)
YOU THEN SCROLL DOWN TO 4: LinReg (ax+b)
GO TO CALCULATE AND PRESS (enter)
Average X and Y
Coordinate
total tuition
the years since 1980
is considered x.)
total tuition
the years since 1980
is considered x.)
Example 1
According to the data in the model, what year will it be when the average
tuition cost is $20,000? y = ax+b
1 ) y = 365.25x + 368.92
3)
20,000 = 365.25x + 368.92
2 ) 20,000 = 365.25x + 368.92
4)
- 368.92
20,000 = 365.25x
20,000 = 365.25x
365.25 365.25
$20,000
Year will be 2033
20,000 = 365.25x
365.25 365.25
20,000 = x
365.25
x = 54.75 +
1978
Example 2
According to the data in the model, how much was the tuition cost in 2020?
y = 365.25x + 368.92
y = 365.25(42) + 368.92
y = 15,340.5 + 368.92
y = 15,709.42
_ 2020
1978
42