The interval of systolic blood pressure lie between 102 and 118.
<h3>What is systolic blood pressure?</h3><h3>Blood pressure is measured using two numbers: The first number, called systolic blood pressure, measures the pressure in your arteries when your heart beats. The second number, called diastolic blood pressure, measures the pressure in your arteries when your heart rests between beats.</h3>
Here, mean blood pressure is 110
and standard deviation is 8
By z table, for 68%,
-1 < z < 1
-1 < (x - μ) / σ < 1
on multiply by σ, we get
-σ < x-μ < σ
on adding μ, we get
-σ + μ < x < σ + μ
-8 + 110 < x < 110 + 8
102 < x < 118
Thus, the interval of systolic blood pressure lie between 102 and 118.
Since its telling you that x is the number of years and the question is "How much does the cost of milk increase EVERY YEAR" then you can conclude that the cost is increasing by 0.25 each year
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