18/20 x 17/19 x 16/18 = 4896/6840, or around 71.6%.
Here is another way to phrase the question: If 18 out of 20 customers make a purchase in a shop, and three customers are selected at random, what is the probablity that all will make a purchase? Each random customer has a 18/20 chance of being one that purchased, so the probability that all three make a purchase is 18/20*18/20*18/20=.729
probability = 2/7 to be exact, 28/97 (about 28.87%)
Approx 0.0287
6 out of 30 ie 20% or 0.2
There is only one girl out of 12 students so the probability that the girl is selected is 1/12.
Here is another way to phrase the question: If 18 out of 20 customers make a purchase in a shop, and three customers are selected at random, what is the probablity that all will make a purchase? Each random customer has a 18/20 chance of being one that purchased, so the probability that all three make a purchase is 18/20*18/20*18/20=.729
The probability is 10 percent.
1/365 = 0.00274
It depends on what the random variable is, what its domain is, what its probability distribution function is. The probability that a randomly selected random variable has a value between 40 and 60 is probably quite close to zero.
probability = 2/7 to be exact, 28/97 (about 28.87%)
.4032
random sample
When each member of the population has the same probability of being selected as a member of the sample.
The probability is approx 0.81
It is a simple random sample.
This is called a random sample.
Approx 0.0287