Statistics Formulae Mean = Li = Ex-xY Sample Variance = S' = F - 1 Some Probability Formulae 1. P(AUB) = P(A)+ P(B) -P(AnB) 2. PLA/B)= P(AnB). P(B) > 0 PB) 3. P(AnB)= P(A/B) * P(B) 4. PLA/B) = PLAY 5. P(AND) = PLA) * P(B) 6. PLA= PAID)PB) P(A/B)P(P(B) P(B/ A)PLA) B. P(A/B)= P(B/ AP(A)+ P(B/ A)P(A) 9. 10. 11. o'=()=EXY -[EX)] 12. PO)= p q = x!(N-x)! 13. u = ni o' =Rpg 14. * * JOP x = 0,1,23... 15. P(x)=pq*-1The weight of a randomly chosen grape of a given variety may be taken to be a normal variable with mean 5g. Find the standard deviation, in grams, given that the probability that a randomly chosen grape weighs less than Jg is 0.123. [3] Find the probability that a randomly chosen grape weighs more than 9g 12] Five grapes are chosen at random. Find the probability that at least two weigh less than [5] Using a suitable approximation, find the probability that, out of 100 randomly chosen grapes at least 3 weigh more than 9g [5]