Finite Math Examples
x>2x>2 , n=3n=3 , p=0.9p=0.9
Step 1
Subtract 0.90.9 from 11.
0.10.1
Step 2
When the value of the number of successes xx is given as an interval, then the probability of xx is the sum of the probabilities of all possible xx values between 00 and nn. In this case, p(x>2)=P(x=3)p(x>2)=P(x=3).
p(x>2)=P(x=3)p(x>2)=P(x=3)
Step 3
Step 3.1
Use the formula for the probability of a binomial distribution to solve the problem.
p(x)=C33⋅px⋅qn-xp(x)=3C3⋅px⋅qn−x
Step 3.2
Find the value of C333C3.
Step 3.2.1
Find the number of possible unordered combinations when rr items are selected from nn available items.
C33=Crn=n!(r)!(n-r)!3C3=nCr=n!(r)!(n−r)!
Step 3.2.2
Fill in the known values.
(3)!(3)!(3-3)!(3)!(3)!(3−3)!
Step 3.2.3
Simplify.
Step 3.2.3.1
Cancel the common factor of (3)!(3)!.
Step 3.2.3.1.1
Cancel the common factor.
(3)!(3)!(3-3)!
Step 3.2.3.1.2
Rewrite the expression.
1(3-3)!
1(3-3)!
Step 3.2.3.2
Simplify the denominator.
Step 3.2.3.2.1
Subtract 3 from 3.
1(0)!
Step 3.2.3.2.2
Expand (0)! to 1.
11
11
Step 3.2.3.3
Divide 1 by 1.
1
1
1
Step 3.3
Fill the known values into the equation.
1⋅(0.9)3⋅(1-0.9)3-3
Step 3.4
Simplify the result.
Step 3.4.1
Multiply (0.9)3 by 1.
(0.9)3⋅(1-0.9)3-3
Step 3.4.2
Raise 0.9 to the power of 3.
0.729⋅(1-0.9)3-3
Step 3.4.3
Subtract 0.9 from 1.
0.729⋅0.13-3
Step 3.4.4
Subtract 3 from 3.
0.729⋅0.10
Step 3.4.5
Anything raised to 0 is 1.
0.729⋅1
Step 3.4.6
Multiply 0.729 by 1.
0.729
0.729
0.729