CORE MATHS PAPER 2
what happens if there is no correlation between two variables?
as one variable increase or decreases the their variable is not affected
does your line of best fit on a scatter graph have to go through 0?
no
how can we reduce variability between different scatter graphs?
add a mean point
what is the mean point?
(means values of x, mean values of y)
does your line of best fit have to go through your mean point?
yes
what is extrapolation?
Predicting data beyond the measured points
What is interpolation?
Inferring data between measured points
what is a regression line?
a more scientific way of drawing a line of best fit
what is the equation of a regression line?
y = a + bx (based off y=mx+c)
what does a and b stand for in the equation of a regression line?
y= a + bx
a= y intercept —> the value of y when x is 0
b= gradient
how do you work out regression lines on your calculator?
MENU SETUP
6
2
put numbers into x and y column
AC
OPTN
3
what is the r value when working out the equation of the regression line?
correlation coefficient
What is a correlation coefficient?
how strong the correlation between two variables is
if r is 1 what does this mean?
it is a perfect positive correlation
if r is 0 what does this mean
there is no linear correlation
if r is -1 what does this mean
there is a perfect negative correlation
if 0.5<r<1 what does this mean
there is a strong positive correlation
what happens if there is no correlation between two variables?
as one variable increase or decreases the their variable is not affected
does your line of best fit on a scatter graph have to go through 0?
no
how can we reduce variability between different scatter graphs?
add a mean point
what is the mean point?
(means values of x, mean values of y)
does your line of best fit have to go through your mean point?
yes
what is extrapolation?
Predicting data beyond the measured points
What is interpolation?
Inferring data between measured points
what is a regression line?
a more scientific way of drawing a line of best fit
what is the equation of a regression line?
y = a + bx (based off y=mx+c)
what does a and b stand for in the equation of a regression line?
y= a + bx
a= y intercept —> the value of y when x is 0
b= gradient
how do you work out regression lines on your calculator?
MENU SETUP
6
2
put numbers into x and y column
AC
OPTN
3
what is the r value when working out the equation of the regression line?
correlation coefficient
What is a correlation coefficient?
how strong the correlation between two variables is
if r is 1 what does this mean?
it is a perfect positive correlation
if r is 0 what does this mean
there is no linear correlation
if r is -1 what does this mean
there is a perfect negative correlation
if 0.5<r<1 what does this mean
there is a strong positive correlation
