Question

N= 17 and P=0.8 is it suitable to use a normal distribution

Answer 1

Since n(1-p) < 10, it is not suitable to use a normal distribution.

Explanation:

Suitability of the normal distribution:

In a binomial distribution with parameters n and p, the normal approximation is suitable is:

np >= 10

n(1-p) >= 10

In this question, we have that:

n = 17, p = 0.8. So

np = 17*0.8 = 13.6 -> Ok

n(1-p) = 17*0.2 = 3.4 -> No

So, since n(1-p) < 10, it is not suitable to use a normal distribution.