Bionomial distribution

Question 1

When does binomial distribution occur

Answer 1

When there are only two possible outcomes for an experiment. When one can be classified as a failure and the other a success

Question 2

When is the binomial distribution a suitable model

Answer 2

-the number of trials is fixed
-the trials are independent
-there are two possible outcomes for each trial

Question 3

What happens when it becomes more than 1 trial

Answer 3

You can use the binomial expansions to find the probability distribution. Use the correct number depending on the amount of success

Question 4

Example question: On a spinner, the probability of landing on blue is 0.4. The spinner is spun four times. Let x be the number of times the spinner lands on blue. Work out P(X=2)

Answer 4

It happens 4 times so use (p+q) ^4
p=0.4 q=0.6
P(X=2) means the number of success is 2. So you use the term where the power of p is equal to the numbers of successes. = 6p^2q^2
Therefore P(X=2) = 6 * 0.4^2 * 0.6^2 =0.3456