Answer:
E(F)=200
V(F)=100
Step-by-step explanation:
(a) Let F be the amount he spends on falafel sandwiches over the next 400 days. Find E[F] and V(F).
If we analized his expenses in falafel sandwiches, we know he buys a $1 sandwich with aprobability of 50%.
If we call the random variable D the daily expense in falafel sandwiches, it is a Bernoulli variable with p=0.50.
If F is the sum of the daily expenses D during the 400 days, then we can say it is a binomial variable with p=0.5 and n=400.
Then we can calculate the expected value of F as:
The variance of F is then