First 190 words of the document:
AS Statistics Revision
Statistics 1 Chapter 7
Key points to remember
Explanatory variable = the variable (usually labelled X) whose
values can be set accurately and which depend only on the
experimenter's choice. Sometimes called the independent
Response variable = the variable (usually labelled Y) whose
values depend upon the values of the explanatory variable.
Sometimes called the dependent variable.
Scatter diagram = the graph of the pairs of the two variables.
The explanatory variable is plotted horizontally and the
variable is plotted variable.
Straight line law = the law of a straight line is given as y=a+bx
where a and b are constants. The gradient of the line is b, and
is the intercept on the yaxis (the value of y when x=0)
a is found with:
a = bx
b is found with:
Sxy ÷ Sxx
Interpolation = using the least squares moder to estimate
value of the response variable within the original range of
of the explanatory variable.