Correlation Coefficient! Question 1 (1 point) The author is a member of the boar
ID: 3229076 • Letter: C
Question
Correlation Coefficient!
Explanation / Answer
Correlation
r( X,Y) =Co V ( X,Y) / S.D (X) * S.D (y)
r( X,Y) = Sum(XY) / N- Mean of (X) * Mean of (Y) / Sqrt( X^2/n - ( Mean of X)^2 ) Sqrt( Y^2/n - ( Mean of Y)^2 )
Co v ( X, Y ) = 1 /5 (1083000) - [ 1/5 *3000 ] [ 1/5 *1310] = 59400
S. D ( X ) = Sqrt( 1/5*2440000-(1/5*3000)^2) = 357.771
S .D (Y) = Sqrt( 1/5*500950-(1/5*1310)^2) = 177.612
r(x,y) = 59400 / 357.771*177.612 = 0.9348
If r = 0.9348> 0 ,Perfect Positive Correlation
PART B.
Given that,
value of r =0.9348
number (n)=5
null, Ho: =0
alternate, H1: !=0
level of significance, = 0.05
from standard normal table, two tailed t /2 =3.182
since our test is two-tailed
reject Ho, if to < -3.182 OR if to > 3.182
we use test statistic (t) = r / sqrt(1-r^2/(n-2))
to=0.9348/(sqrt( ( 1-0.9348^2 )/(5-2) )
to =4.56
|to | =4.56
critical value
the value of |t | at los 0.05% is 3.182
we got |to| =4.56 & | t | =3.182
make decision
hence value of | to | > | t | and here we reject Ho
ANSWERS
---------------
null, Ho: =0
alternate, H1: !=0
test statistic: 4.56
critical value: -3.182 , 3.182
decision: reject Ho
Option A is the answer
( X) ( Y) X^2 Y^2 X*Y 1300 600 1690000 360000 780000 500 195 250000 38025 97500 500 120 250000 14400 60000 400 270 160000 72900 108000 300 125 90000 15625 37500 3000 1310 2440000 500950 1083000 = TOTALS