Approximation to the binomial distrubution

[Biochemgirl2002]

Homework Statement

Consider a binomial random variable with n = 50
trials and p = 1/2.
(A)Is it appropriate to use the normal
approximation to the binomial distribution? If so,
what mean and standard deviation we should we
use when standardizing?

Relevant Equations

X~N(mean, std dev^2)

X~N(np,npq) if np>5 and npq>5

a) since np has to be greater than 5,
n*p= 50*.5
=25
so yes, we can use this since it is much larger than 5.

now, for mean, i believe the equation is saying that the mean is np, which is 25
but in this equation we do not have a q value, so this is where my issue begins...
what should i use for my standard deviation?
do i square it once i find out what q is ?

 

[Mark44]

Homework Statement: Consider a binomial random variable with n = 50
trials and p = 1/2.
(A)Is it appropriate to use the normal
approximation to the binomial distribution? If so,
what mean and standard deviation we should we
use when standardizing?
Homework Equations: X~N(mean, std dev^2)

X~N(np,npq) if np>5 and npq>5

a) since np has to be greater than 5,
n*p= 50*.5
=25
so yes, we can use this since it is much larger than 5.

now, for mean, i believe the equation is saying that the mean is np, which is 25
but in this equation we do not have a q value, so this is where my issue begins...
what should i use for my standard deviation?
do i square it once i find out what q is ?

q is 1 - p, so for this situation, q = 1/2.