In: Statistics and Probability
A particular professor has noticed that the number of people,
P, who complain about his attitude is dependent on the
number of cups of coffee, n, he drinks. From eight days of
tracking he compiled the following data:
People (P) | 10 | 12 | 10 | 10 | 7 | 6 | 6 | 3 |
---|---|---|---|---|---|---|---|---|
Cups of coffee (n) | 1 | 1 | 2 | 2 | 3 | 3 | 4 | 5 |
Unless otherwise stated, you can round values to two decimal
places.
a) Using regression to find a linear equation for P(n)
P(n)P(n) =
b) Find the correlation coefficient
r =
c) Does the correlation coefficient indicate a strong linear trend, a weak linear trend, or no linear trend?
d) Interpret the meaning of the slope of your formula in the context of the problem
e) Interpret the meaning of the P intercept in the context of the problem
f) Use your model to predict the number of people that will complain about his attitude if he drinks 9 cups of coffee.
g) Is the answer to part f reasonable? Why or why not?
h) How many cups of coffee should he drink so that no one will complain about his attitude? It is ok to round to one decimal place.
Setting the table to find the regression equation
Cups of coffee (x) | People (y) | XY | X^2 | Y^2 |
1 | 10 | 10 | 1 | 100 |
1 | 12 | 12 | 1 | 144 |
2 | 10 | 20 | 4 | 100 |
2 | 10 | 20 | 4 | 100 |
3 | 7 | 21 | 9 | 49 |
3 | 6 | 18 | 9 | 36 |
4 | 6 | 24 | 16 | 36 |
5 | 3 | 15 | 25 | 9 |
21 | 64 | 140 | 69 | 574 |
The last row is the summation