Answer:
commutative property
Step-by-step explanation:
You switched the numbers inside the parenthesis, which in this case is 5 and -5.
A) Let x = first score and y = second score
E[x] = 20.9 and E[y] = 20.9
E[x-y] = E[x] – E[y] = 20.9 – 20.9 = 0
b) Standard deviation
= Var[x-y] = Var[x] + Var [y]
= 4.8^2 + 4.8^2 = 46.08
SD[x-y] = sqrt(Var[x-y])
= sqrt(46.08)
= 6.8
c) Z = +/- (mean-x)/SD = +- (0-6)/6.8 = +/- 0.88
From Z table: P(Z<-0.88 or Z>0.88)
= 2*P(Z>0.88)
= 2*0.1894
= 0.3788
a Romance language spoken in Spain and in much of Central and South America (except Brazil) and several other countries. It is the second most widely spoken first language in the world, with more than 400 millon speakers.