U would actually do both...because when ur dividing fractions, u end up multiplying....but u start with dividing.
6 / (1/3) =
6 * 3 = 18 <== ur answer
Answer:
P(X≤5)=0.5357
Step-by-step explanation:
Using the binomial model, the probability that x adults from the sample, are pessimistic about the future is calculated as:

Where n is the size of the sample and p is the probability that an adult is pessimistic about the future of marriage and family. So, replacing n by 20 and p by 0.27, we get:

Now, 25% of 20 people is equal to 5 people, so the probability that, in a sample of 20 American adults, 25% or fewer of the people are pessimistic about the future of marriage and family is equal to calculated the probability that in the sample of 20 adults, 5 people of fewer are pessimistic about the future of marriage and family.
Then, that probability is calculated as:
P(X≤5)= P(1) + P(2) + P(3) + P(4) + P(5)
Where:



Finally, P(X≤5) is equal to:
P(X≤5) = 0.0018+0.0137 + 0.0480 + 0.1065 + 0.1675 + 0.1982
P(X≤5) = 0.5357
Approximately 1718 have a score within that range.
We calculate the z-score for each end of this spectrum:
z = (X-μ)/σ = (2.5-3.1)/0.3 = -0.6/0.3 = -2
Using a z-table (http://www.z-table.com) we see that the area to the left of, less than, this z-score is 0.0228.
For the upper end:
z = (3.7-3.1)/0.3 = 0.6/0.3 = 2
Using a z-table, we see that the area to the left of, less than, this z-score is 0.9772.
The probability between these is given by subtracting these:
0.9772 - 0.0228 = 0.9544.
This means the proportion of people that should fall between these is 0.9544:
0.9544*1800 = 1717.92 ≈ 1718