A total of 447 tickets were sold for the school play. They were either adult tickets or student tickets. They were 53 fewer stud
1 answer:
You might be interested in
Answer:
Step-by-step explanation:
For this case we can use the moment generating function for the normal model given by:
And this function is very useful when the distribution analyzed have exponentials and we can write the generating moment function can be write like this:
And we have that the moment generating function can be write like this:
And we can write this as an infinite series like this:
And since this series converges absolutely for all the possible values of tX as converges the series e^2, we can use this to write this expression:
and we can use the property that the convergent power series can be equal only if they are equal term by term and then we have:
And then we have this:
And then we can find the
And we can find the variance like this :
And first we find:
And then the variance is given by: