Answer:
Option b) r = 0.70
Step-by-step explanation:
We are given the following in he question:
Variables:
x = the number of hours spent studying for a test
y = the number of points earned on the test
- Correlation is a technique that help us to find or define a relationship between two variables.
- A positive correlation means that an increase in one quantity leads to an increase in another quantity
- A negative correlation means with increase in one quantity the other quantity decreases.
- +1 tells about a a perfect positive linear relationship and −1 indicates a perfect negative linear relationship.
- Values between 0 and 0.3 tells about a weak positive linear relationship, values between 0.3 and 0.7 shows a moderate positive correlation and a correlation of 0.7 and 1.0 states a strong positive linear relationship.
- Values between 0 and -0.3 tells about a weak negative linear relationship, values between -0.3 and -0.7 shows a moderate negative correlation and a correlation value of of -0.7 and -1.0 states a strong negative linear relationship.
As the number of hours increases, the number of points earned on the test increases. Thus, the two variables are positively correlated.
Thus, the coefficient correlation between two variables can be given by r = 0.70, that shows a moderate positive correlation.
Option b) r = 0.70
The slope of the line is the gradient, which you can find through rise over run
m (gradient) = (y1 - y2) / (x1 - x2)
where (x1, y1) is the coordinate of the first point, and (x2, x2) is the coordinate of the second point
in your question:
x1 = -4
x2 = 19
y1 = -13
y2 = 11
m = (-13 -11) / (-4 -19) = -24 / -23 = 24/23 or 1.04 (2d.p.)
hope that helps :)
0.69x+4.32=0.46x+3.4
-3.4 -3.4
____________________
0.69x+0.92=0.46x
-0.69x -0.69x
______________
0.92=-0.23
multiply by -100/23 multiply by -100/23
x=-4
Yes there is a 2/3 chance. This is fun stuff!
