Suppose a population consisted of 20 items. How many different sample of n = 3 are possible?Question 13Select one:a.20b.120c.1140d.6840

The number of different samples of n=3 from a population of 20 can be calculated using the combination formula, which is:

C(n, r) = n! / [r!(n-r)!]

where:

• n is the total number of items,
• r is the number of items to choose,
• "!" denotes factorial, which is the product of all positive integers up to that number.

So, in this case, n=20 and r=3. Substituting these values into the formula gives:

C(20, 3) = 20! / [3!(20-3)!] = 20! / [3! * 17!] = (20 * 19 * 18) / (3 * 2 * 1) = 1140

So, there are 1140 different samples of 3 items that can be drawn from a population of 20. Therefore, the correct answer is c. 1140.