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# stastics helpp assingment in for 2morow watch

1. a fair coin is tossed repeatedly until a head appears or 3 tosses have been made. The random variablt T represents the number of tosses of the coin.

a) Find the distrubution of T (3)
b) Find the mean and standard deviation of T (5)
c)Find the probability of obtaining exactly 3 tails on 2 successive attempts, (2)

a discrete random variable x has the probability density function shown in the table below.

x 0 1 2
p(X=x) 1/3 a 2/3-a

a) given that E(X) = 5/6, find the value of the constant a
b) find the exact value of Var (x)
c) Find the exact value of P(x lessthanor euqal to 1.5)
2. a is worth (3)
b (4)
c (1)
3. T can be 1,2 or 3.
P(T=1) means a head must have be thrown, so P(T=1)=0.5
Can you work out the other probabilities?

b) you want E(T) and root of Var(T)...there are formulas given for these.

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