Welcome to the BAII Plus Calculator tutorial for Regression and Correlation coefficients.
I'm Joshua Emmanuel
In this tutorial, we will be calculating the slope, y-intercept, the correlation coefficient and the
coefficient of determination for these data set shown on screen.
Turn the calculator on.
Press 2nd DATA to launch you into the Data Entry mode
Press 2nd CLR WORK
to clear previously done work.
Enter the values: 5 ENTER scroll down
10
ENTER scroll down
9 ENTER scroll down
and 35 ENTER scroll down
scroll down
13 ENTER scroll down
and then 30
ENTER scroll down
7 ENTER scroll down and finally 15 ENTER and stop.
Next press 2nd STAT to reveal the statistics
By default, the BAII Plus calculator reveals linear regression stats
If your calculator does not display LIN on screen press 2nd SET repeatedly
until LIN is displayed
LIN is now displayed. Now press the ↓ button to display the statistics.
n = 4; indicating we entered 4 pairs of values
scroll down
The mean of x is 8.5, the standard deviation
of sample for x is 3.4157
scroll down. If this were a population then population standard deviation for x is 2.958
scroll down. It displays the same set of values for y.
a is the y-intercept which is the value of y
when x is 0. Scroll down, b is the slope
2.714 which is the amount of change in y per unit increase in x.
So if x increases by 1, y will increase on average by 2.714
scroll down
r is the correlation coefficient or coefficient of correlation is 0.7789
and it indicates a strong positive relationship between x and y
To obtain the coefficient of determination r², square the r value
So squaring the r value gives us 0.6067 which is the coefficient of determination and
this means that 60.67% of the variation in y is explained by the variation in x
and about 39.3% is not explained
If you scroll down further, it shows you X' and this is just used to compute
y-value given an x value. So for example when x is 10
what do we expect y to be using the equation we obtained.
So...normally you just plug 10 in for x but you can also input 10 here
ENTER
and then scroll down and compute (CPT)
If x is 10, y will be 26.57
and if you scroll down further here, it shows the sum of x values that we put in
the sum of squared x values, sum of y, sum of y squared, sum of xy
and that's all the statistics displayed by the BAII Plus calculator.
To return to regular calculator mode, press 2nd DATA
2nd CLR WORK
and 2nd QUIT
and now you're back in regular calculator mode again.
Thanks for watching this video. Bye for now.