he time between telephone calls to a cable television service call center follows an exponential distribution with a mean of 1.2 minutes. a. What is the probability that the time between the next two calls will be 45 seconds or​ less? b. What is the probability that the time between the next two calls will be greater than 118.5 ​seconds?

Respuesta :

Answer:

a. The probability that the time between the next two calls will be 45 seconds or​ less is 46%.

b. The probability that the time between the next two calls will be greater than 118.5 seconds is 19%.

Step-by-step explanation:

The cumulative density function of the exponential distribution for x≥0 is:

[tex]F(x;\lambda)=1-e^{-\lambda x}[/tex]

In this case,

[tex]\lambda=1/\mu=1/1.2 \,min^{-1}=\frac{1}{1.2} *\frac{1}{min}*\frac{1\,min}{60s}=  \frac{1}{72} \, s^{-1}[/tex]

a) What is the probability that the time between the next two calls will be 45 seconds or​ less?

The probability that the time between the next two calls will be 45 seconds or​ less is 46%.

[tex]P(x\leq45)=1-e^{45/72}=1-0.54=0.46[/tex]

b) What is the probability that the time between the next two calls will be greater than 118.5 ​seconds?

The probability that the time between the next two calls will be 118.5 seconds or​ less is 19%.

[tex]P(x>45)=1-(1-e^{118.5/72})=e^{118.5/72}=0.19[/tex]