Trick or treaters arrive to your house according to a Poisson process with a constant rate parameter of 20 per hour. Suppose you begin sitting on your front porch, observing these arrivals, at some point in time. Suppose a trick or treater arrived 30 minutes ago, but there have been none since. What is the expected value of interarrival time (in minutes) from the previous trick or treater to the next one

The expected value of interarrival time (in minutes) from the previous trick or treater to the next one is 3 minutes.

Step-by-step explanation:

We have a Poisson process with a constant rate parameter of 20 arrival per hour.

This type of processes are memory-less, meaning that no matter how much time has passed form the last event, the probabilities of an arrival stay the same.

The mean interarrival time can be calculated as the inverse of the mean arrival for the Poisson process.

If the Poisson process has a rate of 20 arrivals per hour, the mean interarrival time is:

at home andrea has 1 2/3 kilograms of rice

step-by-step explanation:

for the friend request.

when a figure, such as triangle (xyz) is reflected over the line y = x to create x'y'z' the x-coordinates and y-coordinates of the original image (pre-image) will be reversed for the image. (e.g., (x, y) > (y, x)) this means that the pre-image position of the x- and y-coordinates switch places which in turn provides a mirror like image of the original xyz.  

i notice that when i draw a line segment from x to x', that the points are parallel from each other -- they are exactly across from each other and do not intersect with any other points.  

yes, think i would see the same characteristic if you drew the line segment connecting y with the reflecting line and then y' with the reflecting line because of the essence of reflections. because it is a mirror image, each point was effected the same way which leads me to conclude that they same would apply to y and y'.