To obtain the probability distribution of X, which represents the number of adults against using animals for research in a random sample of two adults, we can use the concept of binomial distribution.
In this case, we have a binomial experiment because each adult can be classified as either being against using animals for research or not. The probability of success (p) is given as 35%, which can be written as 0.35.
The formula for the probability mass function (PMF) of the binomial distribution is:
P(X = k) = (n choose k) * p^k * (1-p)^(n-k)
Where:
- P(X = k) represents the probability of having k successes
- (n choose k) is the binomial coefficient, which can be calculated as n! / (k!(n-k)!)
- p is the probability of success (35% or 0.35 in our case)
- k is the number of successes we want to calculate the probability for
- n is the number of trials or sample size (2 in this case)
Using this formula, we can calculate the probabilities for each possible value of X in the sample of two adults.
For X = 0 (both adults are against using animals for research):
P(X = 0) = (2 choose 0) * 0.35^0 * (1-0.35)^(2-0)
= (1) * 1 * 0.65^2
= 0.65^2
= 0.4225
For X = 1 (one adult is against using animals for research):
P(X = 1) = (2 choose 1) * 0.35^1 * (1-0.35)^(2-1)
= (2) * 0.35 * 0.65^1
= 0.455
For X = 2 (both adults are against using animals for research):
P(X = 2) = (2 choose 2) * 0.35^2 * (1-0.35)^(2-2)
= (1) * 0.35^2 * 1^0
= 0.1225
Therefore, the probability distribution of X for the random sample of two adults is as follows:
P(X = 0) = 0.4225
P(X = 1) = 0.455
P(X = 2) = 0.1225