Dr. Sabbaghi is taking two flights today. The flight time for the first flight is Normally distributed with a mean of 90 minutes and a standard deviation of 3 minutes. The flight time for the second flight is Normally distributed with a mean of 110 minutes and a standard deviation of 4 minutes. His total flight time today has what type of distribution with what mean and standard deviation?

Since X and Y are independent then and we have this:

And the deviation would be given by:

And then the distribution for the total time would be given by:

Step-by-step explanation:

For this case we can assume that X represent the flight time for the first filght and we know that:

And let Y the random variable that represent the time for the second filght and we know this:

And we can define the random variable Z= X+Y as the total time for the two flights.

We can asume that X and Y are independent so then we have this:

Since X and Y are independent then and we have this:

And the deviation would be given by:

And then the distribution for the total time would be given by:

step-by-step explanation: