Answer:
0.213
Step-by-step explanation:
This is a probability question.
Let c = probability of a student taking chemistry. That is 40% = 4/10
Now, let d be the probability of a student not taking chemistry, that would be 60% = 6/10
Now out of 12 sampled, we want to calculate the probability that exactly 4 have taken chemistry.
The easiest approach here is by the use of bernoulli approximation.
Thus,
P(x = 4) = 12C4 * c^4 * d^8
P(x =4) = 12C4 * (0.4)^4 * (0.6)^8
P(x = 4) = 495 * 0.0256 * 0.01679616
P(x = 4) = 0.2128
To the nearest thousandth, the probability is 0.213
