Lifetimes of electronic components can often be modeled by an exponential model. Suppose quality control engineers want to model the lifetime of a hard drive to have a mean lifetime of 4 years. Complete parts a and b below. a) What value of should they use? They should use a value of 0.25 for i (Type an integer or a fraction) b) With this model. What would the probability be that a hard drive lasts 4 years or less? The probability is N1 (Type an integer or a decimal. Round to three decimal places as needed)