Solve thus system by substitution
2 answers:
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Answer:
Therefore the mean and standard deviation of his total score if he plays a full 18 holes are 160 and respectively.
Step-by-step explanation:
Given that,
For the first 9 holes X:
E(X) = 80
SD(X)=13
For the second 9 holes Y:
E(Y) = 80
SD(Y)=13
For the sum W=X+Y, the following properties holds for means , variance and standard deviation :
E(W)=E(X)+E(Y)
and
V(W)=V(X)+V(Y)
⇒SD²(W)=SD²(X)+SD²(Y) [ Variance = (standard deviation)²]
∴E(W)=E(X)+E(Y) = 80 +80=160
and
∴
Therefore the mean and standard deviation of his total score if he plays a full 18 holes are 160 and respectively.