Discrete uniform distribution? S1

Hi -

I'm just going through Solomon papers and i'm asked to work out the standard deviation and mean of some values from a grouped frequency distribution, but then it asks me to work out the mean that a discrete uniform distribution would predict?

Please could someone explain this to me? The answer with the grouped frequency distribution for mean is 5.05

Thanks

Reply 1

Darkest Knight

anyone?

Reply 2

jbuck100

i think discrete uniform distribution is where each value of x has the same probablilty
i.e. x: 1 2 3 4
P(X=x): 1/4 1/4 1/4 1/4
so the mean is the middle value, 2.5 in this case. does that help?

Reply 3

angad7.10

ok see jbuck was right, a discrete uniform distribution has the same P(X=x) for all the values. the mean of a discrete uniform distribution would be E(X)
and the E(X) of a discrete uniform distribution is always the same as the probabilty. like if i have x values - 1,2,3,4,5
probability of each would be 1/5,1/5,1/5,1/5,1/5
therefore Mean[E(X)] would be 1/5

Reply 4

jbuck100

im not sure what you meant by that, how can the mean of 1 2 3 4 5 be 1/5?...
i think darkest knight means he has to work out E(X), which in the case of 1 2 3 4 5 would be 3