Question

given a binomial distribution with n = 20 and p = 0.26, would the normal distribution provide a reasonable approximation? why or why not?

Answer 1

you tend to want values of n that are 30 or greater

Answer 2

besides that the normal is a good approximation; but you have to account for errors that creep in as a result of equating a continuous count with a discrete count

Answer 3

mean = np
variance = npq
sd = sqrt(npq)

Answer 4

where q = -p

Answer 5

err ... 1 - p

Answer 6

Because the normal approximation is not accurate for small values of n, a good rule of thumb is to use the normal approximation only if np>10 and np(1-p)>10.

http://www.stat.yale.edu/Courses/1997-98/101/binom.htm

Answer 7

np here is about 5

Answer 8

thank you tha make more sense

Answer 9

yep