a casual relationship is where
there is a reason why something happens
example of a casual relationship is
as the age of something increases its value decreases
with lines of best fit, if you have to plot it through the mean point, it means
find the mean of x and the mean of y and plot that point
interpolation is
within the data and therefore is reliable
extrapolation is
outside the data set and is therefore less reliable than interpolation
line of best fit is also known as
the regression line
equation of a line is
y=mx+c
gradient means that
every time that x increases by 1 the y increases/decreases by m
the y intercept is
the initial thing as it is where x is zero
spearman’s rank tests
how strong or weak the correlation between two things are
the equation for spearmans rank is
in spearman’s, a perfect positive or negative correlation is
1 or -1
in spearmans, a strong positive or negative correlation is
0.8 or above, -0.8 or below
in spearman’s a weak positive or negative correlation is
0.4 or above, -0.4 or below
in spearman’s you have to rank both x and y
the same way
spearman’s rank is represented as
rs
spearman’s rank is designed for
non-linear correlation
what is more suitable for linear correlation
pearsons product moment correlation