Answer:
a) Probability that exactly 29 of them are spayed or neutered = 0.074
b) Probability that at most 33 of them are spayed or neutered = 0.66
c) Probability that at least 30 of them are spayed or neutered = 0.79
d) Probability that between 28 and 33 (including 28 and 33) of them are spayed or neutered = 0.574
Step-by-step explanation:
This is a binomial distribution question
probability of having a spayed or neutered dog, p = 0.67
probability of having a dog that is not spayed or neutered, q = 1 - 0.67
q = 0.23
sample size, n = 48
According to binomial distribution formula:
[tex]P(X=r) = nCr p^r q^{n-r}[/tex]
where [tex]nCr = \frac{n!}{(n-r)! r!}[/tex]
a) Probability that exactly 29 of them are spayed or neutered
[tex]P(X= 29) = 48C29 * 0.67^{29} * 0.23^{19}\\P(X=29) = 0.074[/tex]
b) Probability that at most 33 of them are spayed or neutered
[tex]P(X \leq 33) =1 - P(X > 33)\\P(X \leq 33) =1 - 0.34\\P(X \leq 33) = 0.66[/tex]
c) Probability that at least 30 of them are spayed or neutered
[tex]P(X \geq 30) = 1 - P(x < 30)\\P(X \geq 30) = 1 - 0.21\\P(X \geq 30) = 0.79[/tex]
d) Probability that between 28 and 33 (including 28 and 33) of them are spayed or neutered.
[tex]P(28 \leq X \leq 33) = P(X=28) + P(X=29) + P(X=30) + P(X=31) + P(X=32) + P(X=33)\\P(28 \leq X \leq 33) = 0.053 + 0.074 + 0.095 + 0.112 + 0.121 + 0.119\\P(28 \leq X \leq 33) = 0.574[/tex]