a. The events are mutually exclusive, so
b. For the same reason,
Another way to see this is to use the result from part (a), and the inclusion/exclusion principle:
and the right side reduces to 0.
c. Same as (b),
d. Same as (b),
We can also use the distributivity rule for unions and intersections to write
e. If the is the complement of
, then by DeMorgan's law,
Answer:
And using the cdf we got:
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:
And 0 for other case. Let X the random variable that represent the random variable of interest and we know that the distribution is given by:
We know the variance on this case given by :
So then the deviation is given by:
And if we solve for we got:
The cumulative distribution function for the exponential distribution is given by:
Solution to the problem
And for this case we want to find this probability:
And using the cdf we got: