218k views
1 vote
For a binomial distribution with n = 12

p = 0.25. What is the probability that x is older than 2?

User Alariva
by
8.4k points

1 Answer

4 votes

Final answer:

To find the probability that in a binomial distribution with n=12 and p=0.25, the number of successes x is greater than 2, one should use the binomcdf function on a calculator with the correct parameters and then subtract this from 1 to get the desired probability.

Step-by-step explanation:

The student has asked about calculating the probability for a binomial distribution. Specifically, for a binomial distribution with n = 12 trials and a success probability of p = 0.25, the student wants to know the probability that the number of successes x is greater than 2. This can be calculated using the complement rule of probabilities since calculating directly for x > 2 would involve summation of many probabilities, which is complex without the aid of technology. Instead, one can find P(x ≤ 2) and then subtract this from 1 to obtain P(x > 2).

To find P(x > 2) using a graphing calculator like the TI-83 or 84, one would typically use the binomcdf function. However, there is an error in the provided instructions; they should instead direct to inputting the correct parameters for our case (n=12, p=0.25, x=2). The formula will be:

1 - binomcdf (12, 0.25, 2)

This command gives the complement probability of getting at most 2 successes in 12 trials, which is then subtracted from 1 to find the probability of getting more than 2 successes.

User Octavio Del Ser
by
8.2k points