A random variable X has the probability distribution
value 1 2 3 4
probability 0.5 0.25 0.125 0.125
(For those of you who are interested, this is the geometric p=0.5 “killed” at 4. X is the number of times I toss a coin if I follow this rule: I’ll toss the coin till I get the first head, but I’ll stop after 4 tosses even if I haven’t got a head by that time.)

Find SE(X)

Question

A random variable X has the probability distribution
value                1         2             3              4
probability       0.5     0.25       0.125       0.125
(For those of you who are interested, this is the geometric p=0.5 “killed” at 4. X is the number of times I toss a coin if I follow this rule: I’ll toss the coin till I get the first head, but I’ll stop after 4 tosses even if I haven’t got a head by that time.)

Find SE(X)

amistre64 · Answer

the standard error of X ?    what does that notation stand for

amistre64 · Answer

if so, then its the deviation divided by the sqrt(n) , n=4 in this case

amistre64 · Answer

deviation of a Bprob is sqrt(npq)

amistre64 · Answer

soo,  sqrt(.5*.5) = .5

anonymous · Answer

http://openstudy.com/users/pakinam#/updates/51855ff5e4b0bc9e008a5379

amistre64 · Answer

ahh ... helps to know the notation :)