00:01
The number of students who seek assistance with statistics assignments, let's call that random variable x, is a poisson random variable with a mean of 2 per day.
00:13
Now for part a we were asked for the probability that no students seek assistance tomorrow.
00:19
So tomorrow is a duration of one day.
00:22
So let's first provide the probability mass function for the poisson random variable.
00:29
Is a parameter lambda times t, the exponent x times e to the minus lambda t, over x factorial, and x can be any integer from zero onward.
00:51
So our mean of 2 per day is the parameter lambda, which is known as the rate parameter or the average rate.
01:01
And we've defined this in the basic time unit of one day.
01:05
So we have lambda is 2 per day, and then for a, we're asked for the probability that no students seek assistance in one day, so time is one day, so lambda times t is equal to 2...