The method of least squares was used to ﬁt a straight line model to these
data. The equation of the least squares ﬁt line is
y = 98.7 + 0.971x.
(a) Choose more meaningful labels for the explanatory and dependent
variables, and hence write down an equation that may be used to
model the relationship between a person’s age and their blood
(b) Use this equation to predict the systolic blood pressure for a person
whose age is 45 years.
(c) Person A is 5 years older than Person B. According to the model,
what is the predicted diﬀerence between the systolic blood pressures
of Person A and Person B?
a. Let replace y by BP (blood presure) and x by AY (age )
so model become
b. BP=98.7+.971 x 45
c. difference in BP of A and B= 5x.971
because model is linear so BP also changes linearly.
(98.7+.971(x+5)-(98.7+.971 x)= 5 (.971)=4.86)