Exact Area = 98pi
Approximate Area = 307.8760800518 (use calculator stored version of pi)
Approximate Area = 307.72 (using pi = 3.14)
Units are in square millimeters
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Explanation:
In 60 seconds, the hand sweeps out a full circle of radius 14. The area of this circle is
A = pi*r^2 = pi*14^2 = 196pi
Half of this is what the hand sweeps out in 30 seconds, so A/2 = (196pi)/2 = 98pi is the exact area it sweeps out. Your calculator would then show 98pi = 307.8760800518 approximately
If instead you use pi = 3.14, then the approximate area is 98*3.14 = 307.72
Answer:
a) y = 0.74x + 18.99; b) 80; c) r = 0.92, r² = 0.85; r² tells us that 85% of the variance in the dependent variable, the final average, is predictable from the independent variable, the first test score.
Step-by-step explanation:
For part a,
We first plot the data using a graphing calculator. We then run a linear regression on the data.
In the form y = ax + b, we get an a value that rounds to 0.74 and a b value that rounds to 18.99. This gives us the equation
y = 0.74x + 18.99.
For part b,
To find the final average of a student who made an 83 on the first test, we substitute 83 in place of x in our regression equation:
y = 0.74(83) + 18.99
y = 61.42 + 18.99 = 80.41
Rounded to the nearest percent, this is 80.
For part c,
The value of r is 0.92. This tells us that the line is a 92% fit for the data.
The value of r² is 0.85. This is the coefficient of determination; it tells us how much of the dependent variable can be predicted from the independent variable.
I think it's (h= $6.25) because if you divide all y's by x you will get 6.25 every time. so the answer is most likely $6.25
