we are given
f(x)=[x=1]
where bracket means ceiling functions
we know that
Ceiling function returns the least value of the integer that is greater than or equal to the specified number
so, we can check each options
option-A:
At x=-4:
f(x)=[-4-1] =-5
For x<-3:
Let's assume
x=-3.1
f(x)=[-3.1-1] =[-4.1]=-5
so, this interval is TRUE
option-B:
At x=-2:
f(x)=[-2-1] =-3
For x<-1:
Let's assume
x=-1.1
f(x)=[-1.1-1] =[-2.1]=-3
so, this is FALSE
Answer:
a) The total gross sales over the next 2 weeks exceeds $5000 is 0.0321.
b) The weekly sales exceed $2000 in at least 2 of the next 3 weeks is 0.9033.
Step-by-step explanation:
Given : The gross weekly sales at a certain restaurant are a normal random variable with mean $2200 and standard deviation $230.
To find : What is the probability that
(a) the total gross sales over the next 2 weeks exceeds $5000;
(b) weekly sales exceed $2000 in at least 2 of the next 3 weeks? What independence assumptions have you made?
Solution :
Let and
denote the sales during week 1 and 2 respectively.
a) Let
Assuming that and
follows same distribution with same mean and deviation.
So,
The total gross sales over the next 2 weeks exceeds $5000 is 0.0321.
b) The probability that sales exceed teh 2000 and amount in at least 2 and 3 next week.
We use binomial distribution with n=3.
Let Y be the number of weeks in which sales exceed 2000.
Now,
So,
The weekly sales exceed $2000 in at least 2 of the next 3 weeks is 0.9033.