This
is only true if A and B are independent. You can never assume A and B
are independent. You must either know it or prove it.
A Level Maths Notes: S1 – Summary of Formulae, Conditional Probability, Independent Events etc
This
is only true if A and B are independent. You can never assume A and B
are independent. You must either know it or prove it.
This
is always true for two events A and B. The left hand side P(A divides
B) is the probability that A will happen given that B has happened,
often written as A given B or A conditional on B. If A and B are
independent then
so
This
is always true.
The above equations are very useful when working with Venn diagrams.
Correlation Coefficients and Regression Lines
where
If the equation of a regression line of
on
is
given by
then
and
The unbiased estimate of the standard deviation of a
random variable
found
from a list of n numbers
is
given by
where
If the expectation value – often called the mean,
average, and written
or
–
of a random variable
is
given by
and
then
and
and
for
all distributions, but if the distribution is continuous we may
use
and
and
for
a continuous distribution etc.
for
a continuous distribution.