Exponential distribution

Question

The lifetime of a new television has an exponential distribution with an average lifetime of 7.5 years. As a sales incentive the company offers guaranteed free replacement for any tv that fails within one year. What percentage of tvs will the company need to replace?

Answer 1

The formula for the PDF of an exponential distribution is f(x)=λe^-λx were the mean is 1/λ.

 

The question asks for the percentage of tvs that with 0<x<1 with x=#yrs.

 

You need to integrate f(x) from 0 to 1 or use an online exponential calculator.

 

Need any additional steps or explanation comment back.