# The method of least squares was used to ﬁt a straight line model to thesedata. The equation of the least squares ﬁt line is y = 98.7 + 0.971x.(a) Choose more meaningful labels for the...

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

pressure.

(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?

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### 1 Answer

a. Let replace y by BP (blood presure) and x by AY (age )

so model become

BP=98.7+.971AY

b. BP=98.7+.971 x 45

BP=142.395

BP=142.40 (approx.)

c. difference in BP of A and B= 5x.971

=4.86

because model is linear so BP also changes linearly.

(**98.7+.971(x+5)-(98.7+.971 x)= 5 (.971)=4.86)**