# Math Help - probability

1. ## probability

the average pass % in a test is 70. find out the probability tht out of a group of 8 students atleast 5 pass.

2. Originally Posted by Zandra
the average pass % in a test is 70. find out the probability tht out of a group of 8 students atleast 5 pass.
Do you mean that the average number of students who pass a test is 70% ? If so, then:

Let X be the random variable number of students who pass.

X ~ Binomial(n = 8, p = 0.7)

Calculate $\Pr(X \geq 5)$.

3. Originally Posted by Zandra
the average pass % in a test is 70. find out the probability tht out of a group of 8 students atleast 5 pass.

Try Binomial distribution
X-B(8 , 7/10)
Let x be the random variable of students passing the test .

$P(X\geq5)$

4. thankyou