This is kinda hard to explain but I'll try my best. Here's a tip, the fractions that are on the ruler really mean 10,20,30,40,50,60,70,80,90, and 100. So, when you look at the decimals on number 7, you have to try to turn them into fractions in your head. For example, 0.9 is actually 9/10 or 90.
Sure, what do you want to talk about??
Paul's rate before the pay rise = 7.0
The increase = 4/100 * 7.0 = 0.28
Paul's rate after the pay rise = 7.0 + .28 = 7.28
This question is incomplete, the complete question is;
X and Y are independent Gaussian (Normal) random Variables. X has mean 13.9 and variance 5.2; Y has mean 6.9 and variance 3.8. . (a) Calculate P( W> 10)
Answer:
P( W> 10) is 0.1587
Step-by-step explanation:
Given that;
X ⇒ N( 13.9, 5.2 )
Y ⇒ N( 6.9, 3.8 )
W = X - Y
Therefore
E(W) = E(X) - E(Y)
= 13.9 - 6.9 = 7
Var(W) = Var(X) + Var(Y) -2COV(X.Y)
[ COV(X,Y) = 0 because they are independent]
Var(W) = 5.2 + 3.8 + 0
= 9
Therefore
W ⇒ N( 7, 9 )
so
P( W > 10 )
= 1 - P( W ≤ 10 )
= 1 - P( W-7 /3 ≤ 10-7 /3 )
= 1 - P( Z ≤ 1 ) [ Z = W-7 / 3 ⇒ N(0, 1) ]
from Standard normal distribution table, P( Z ≤ 1 ) = 0.8413
so
1 - P( Z ≤ 1 ) = 1 - 0.8413 = 0.1587
Therefore P( W> 10) is 0.1587
The answer is X=-3 and y=6 to make the equation true
