Answer:
P ( X < 4 ) = 0.1736706
Step-by-step explanation:
Given:
- A random variable X follows a binomial distribution as follows,
Where n = 8, and p = 0.6.
Find:
- P ( X < 4 )?
Solution:
- The random variable X follows a binomial distribution as follows:
X ~ B ( 8 , 0.6 )
- The probability mass function for a binomial distribution is given as:
pmf = n^C_r ( p )^r (1-p)^(n-r)
- We are asked to find P ( X < 4 ) which is the sum of following probabilities:
P ( X < 4 ) = P ( X = 0 ) + P ( X = 1 ) + P ( X = 2 ) + P ( X = 3 )
- Use the pmf to compute the individual probabilities:
P ( X < 4 ) = 0.4^8 + 8^C_1*(0.6)*(0.4)^7 + 8^C_2*(0.6)^2*(0.4)^6 + 8^C_3*(0.6)^3*(0.4)^5 .
P ( X < 4 ) = 6.5536*10^-4 + 7.86432*10^-3 + 0.04128768 +0.12386304
Answer: P ( X < 4 ) = 0.1736706
