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Using the y=mx+c, find how tall a player will be if they get 3 rebounds. 

 

Pictures :

  http://imgur.com/a/24Wbn

DATA IS AS FOLLOWS.

198, 9

187, 2

201, 13

184, 3

204, 4

179, 2

210, 18

185,3

202,11

196,7

205,15

189,16

Data in table continues, the 2 tables are one, just split due to size limits.

X Values range from 179 - 210 ( on data table)

Y values range from 0 - 18 ( on data table)

When i try to work this problem out, i pick two points to find the gradient, in this case:

(182, 4) AND (203,12)

Then use formula to figure out graident:

M=Y2-Y1 OVER X2-X1

= 12-4 OVER 203-185 = 0.4444

M= 0.4444

 

Then i find Y intercept, using algabra ( teacher said to )

 

I choose one coord, then sub values into equation.

(185,4)

4=0.4444 X 185 + C

4=82.214 + C

4-82.214= C

C= -78.214

Equation is Y=0.4444X - -78.214

So i then do:
Y=0.4444 X 3 - -78.214

= 79.5472

But on my line of best fit, it should be  183 in height, not 79. What have i done wrong? i am so confused! Thank you for your time

 Jul 30, 2015

Best Answer 

 #1
avatar+118587 
+5

 

 

 

Unless i have entered the values wrongly, Excel shows me that for 3 rebounds the expected height is approx 188.5cm

If i use the regression formula that Excel gave me

y=0.4063x-70.647

$${\mathtt{3}} = {\mathtt{0.406\: \!3}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{70.647}} \Rightarrow {\mathtt{x}} = {\frac{{\mathtt{736\,470}}}{{\mathtt{4\,063}}}} \Rightarrow {\mathtt{x}} = {\mathtt{181.262\: \!613\: \!832\: \!143\: \!736\: \!2}}$$

 

 

It can't be 79, no one in the sample is that short :))

 Jul 30, 2015
 #1
avatar+118587 
+5
Best Answer

 

 

 

Unless i have entered the values wrongly, Excel shows me that for 3 rebounds the expected height is approx 188.5cm

If i use the regression formula that Excel gave me

y=0.4063x-70.647

$${\mathtt{3}} = {\mathtt{0.406\: \!3}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{70.647}} \Rightarrow {\mathtt{x}} = {\frac{{\mathtt{736\,470}}}{{\mathtt{4\,063}}}} \Rightarrow {\mathtt{x}} = {\mathtt{181.262\: \!613\: \!832\: \!143\: \!736\: \!2}}$$

 

 

It can't be 79, no one in the sample is that short :))

Melody Jul 30, 2015
 #2
avatar+118587 
0

Do you need me to do it with the two points that you randomly chose?

Or can you work that out now.  

I used the proper regression line but the idea is the same and the answers should be more or less similar :)

 Jul 30, 2015

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