# Data was collected on age (in years) and blood pressure (in millimeters of mercury) from a sample of people living in a particular country. A scatterplot of the data was produced. The method of...

Data was collected on age (in years) and blood pressure (in millimeters of mercury) from a sample of people living in a particular country. A scatterplot of the data was produced.

The method of least squares was used to fit a straight line model to this data. The equation of the least squares fit line is

y = 98.7 + 0.971*x*

a) choose more meaningful labels for the explanatory and dependant 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 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 prediced difference between the blood pressures of person A and person B?

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### 1 Answer

a. Let write presure (P) for y and and age in year ( A) for x .Thus model will become

P=98.7 + 0.971* A*

*.971A=P- 98.7*

*A=(P-98.7)/.971 (i)*

*b. We have age 45 years.*

*P= 98.7+0.971 x (45)*

*=142.395 mm*

*c. Let age of Person B= x years ,so age of Person A=x+5*

*PB=Blood presure of person B= 98.7+.971x*

*PA= Blood presure of person A=98.7+.971(x+5)*

*difference in Blood presure= PA-PB*

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

*=.971 x 5*

*=4.855 mm *