Answer:
a) 1; b) 0.95; c) 0.0574; d) 0.0128; e) 0.0127
Step-by-step explanation:
For part a,
To find the number we would expect (the mean), we multiply the sample size by the probability of success:
10(0.1) = 1
For part b,
To find the standard deviation, we use
[tex]\sqrt{npq}[/tex]
Our n is 10, p is 0.1; this makes q = 1-0.1 = 0.9:
[tex]\sqrt{10(0.1)(0.9)}=\sqrt{0.9}\approx 0.95[/tex]
For part c,
We use the binomial table, looking up P(X = 3): 0.0574
For part d,
We start out finding P(X ≤ 3): 0.9872. However, we want P(X > 3), so we subtract from 1:
1-0.9872 = 0.0128
For part d,
We find P(X ≤ 3) and P(X ≤ 5) then subtract:
P(X ≤ 3) = 0.9872; P(X ≤ 5) = 0.9999
0.9999-0.9872 = 0.0127