Question

HELP! WILL MEDAL + FAN

The table shows overall class grades for students at different heights.

Height 64 65 66 67 68 69 70 71 72 73
Overall class grade 100 71 71 64 62 89 60 77 72 99

Calculate the correlation coefficient.
0.55

0.50

0.05

0.00

Answer 1

@texaschic101 @amistre64 @thomaster

Answer 2

Imma find the mean of teh Height, then Imma find the mean of teh Overall Class Grade.

Determining The Mean Height:

(64 + 65 + 66 + 67 + 68 + 69 + 70 + 71 + 72 + 73) / 10

...This gets us: 685/10; and this equals 68.5. There's our Mean Height.

Okey-dokey. Now we determine the Mean Overall Class Grade.

(100 + 71 + 71 + 64 + 62 + 89 + 60 + 77 + 72 + 99) / 10

...And THAT equals 76.5. This is our Mean Overall Class Grade. Kay-kay. Now we subtract the average of the Class Grade from each original term in the Overall Class Grade section. We do this same thing to the Height section.

This is what I get when I follow through with that process:

For the Mean Height:
(-4.5) + (-3.5) + (-2.5) + (-1.5) + (-0.5) + (0.5) + (1.5) + (2.5) + (3.5) + (4.5)

For The Mean Overall Class Grade:
(23.5) + (-5.5) + (-5.5) + (-12.5) + (-14.5) + (12.5) + (-16.5) + (0.5) + (-4.5) + (22.5)

Now I need to multiply The Mean Overall Class Grade by the Mean Height for each term.
Like this:

(-4.5) is the first term for our modified Mean Height, so multiply it the first term in our modified Mean Overall Class Grade; AKA (23.5).
(-3.5) is the second term for our modified Mean Height, so multiply it the second term in our modified Mean Overall Class Grade; AKA (-5.5).
You get the idea.

Okay.

When you get your results, of which there should be 10, add them all up.

We get: 21.5 as our answer.

Go back to the modified Mean Height and square each term there. Also square each term in the modified Mean Overall Class Grade.

For the modified Mean Height, we should get:
(20.25) + (12.25) + (6.25) + (2.25) + (0.25) + (0.25) + (2.25) + (6.25) + (12.25) + (20.25), and this adds all up to: 82.5.

For the modified Mean Overall Class Grade, we should get:
(552.25) + (30.25) + (30.25) + (156.25) + (210.25) + (156.25) + (272.25)+ (0.25) + (20.25) + (506.25), and this adds up to: 1934.5.

Divide: (21.5) / (sqr-root(82.5*1934.5) ), and you have your correlation coefficient.

0.54 is what I get all up in here.

Choice A looks like teh best choice.

Answer 3

It was C

Answer 4

Interesting. How'd you come to that conclusion? Love to know!