Fast food restaurants pride themselves in being able to fill orders quickly. A study was done at a local fast food restaurant to determine how long it took customers to receive their order at the drive-thru. It was discovered that the time it takes for orders to be filled is exponentially distributed with a mean of 1.5 minutes. What is the probability that it takes less than one minute to fill an order

Respuesta :

Answer:

[tex] X \sim Exp (\lambda =1.5)[/tex]

For this case we want to find this probability:

[tex] P(X <1)[/tex]

And we can use the cumulative distribution given by:

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

And replacing we got:

[tex] P(X<1) = 1- e^{-1.5 *1}= 1-0.2231=0.7769[/tex]

Step-by-step explanation:

Previous concepts

The exponential distribution is "the probability distribution of the time between events in a Poisson process (a process in which events occur continuously and independently at a constant average rate). It is a particular case of the gamma distribution". The probability density function is given by:

[tex]P(X=x)=\lambda e^{-\lambda x}[/tex]

Solution to the problem

For this case we can define the random variable X= "how long it took customers to receive their order at the drive-thru"

And the distribution for X is given by:

[tex] X \sim Exp (\lambda =1.5)[/tex]

For this case we want to find this probability:

[tex] P(X <1)[/tex]

And we can use the cumulative distribution given by:

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

And replacing we got:

[tex] P(X<1) = 1- e^{-1.5 *1}= 1-0.2231=0.7769[/tex]