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# someone help with s1 question pls watch

1. Question a) ii
2. The mean is E (X) which is the summation of the X values multiplied by their corresponding probabilities. The variance is
E (X^2 ) - (E (X))^2 )
3. (Original post by Radioactivedecay)
The mean is E (X) which is the summation of the X values multiplied by their corresponding probabilities. The variance is
E (X^2 ) - (E (X))^2 )
Apparently the mean= 10/6 and variance= 50/36

but I couldn't get that from using those formulas
4. Ive tried using mean = np and variance = np(1-p)
5. (Original post by aceplayyt)
Apparently the mean= 10/6 and variance= 50/36

but I couldn't get that from using those formulas
X here is the number of times you get the number 6.
Probability is 1/6.
But since here is only one value, E (X) would simply be the number of trials times the probability, which is 10 times 1/6.

For the Variance you essentially do the mean of the squares minus the square of the mean.

In this case Var (X)= E (X^2 ) - (10/6)^2
6. (Original post by Radioactivedecay)
X here is the number of times you get the number 6.
Probability is 1/6.
But since here is only one value, E (X) would simply be the number of trials times the probability, which is 10 times 1/6.

For the Variance you essentially do the mean of the squares minus the square of the mean.

In this case Var (X)= E (X^2 ) - (10/6)^2
This is not going into my head aha

So to get E(X^2) you do (10^2)*1/6 - (10/6)^2 ?
7. Dont worry i got it now

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