Answer:
Probability that more than eight but fewer than 12 of the 20 constituents sampled believe their representative possesses low ethical standards is 0.417890.
Step-by-step explanation:
We are given that the paper claims that 43% of all constituents believe their representative possesses low ethical standards.
Suppose 20 of a representative's constituents are randomly and independently sampled.
The above situation can be represented through binomial distribution;
where, n = number of trials (samples) taken = 20 constituents
r = number of success = more than eight but fewer than 12
p = probability of success which in our question is probability that
all constituents believe their representative possesses low
ethical standards, i.e; p = 43%
Let X = <u><em>Number of constituents who believe their representative possesses low ethical standards</em></u>
So, X ~ Binom(n = 20 , p = 0.43)
Now, Probability that more than eight but fewer than 12 of the 20 constituents sampled believe their representative possesses low ethical standards is given by = P(8 < X < 12)
P(8 < X < 12) = P(X = 9) + P(X = 10) + P(X = 11)
=
=
= <u>0.417890</u>
<u></u>
Hence, the required probability is 0.417890.