Homework Statement
f(x) = (3/4)(-x^2 + 6x - 8) for 2 < x < 4 (0 elsewhere)
A) Find F(x)
integral 2 to 4 ((3/4)(-x^2 + 6x - 8))dx
B) Use F(x) to find P(3 < X < 3.5)
integral 3 to 3.5 ((3/4)(-x^2 + 6x - 8))dx
11/32
C) Use F(x) to find P(X > 3.5)
1-( P(3 < X < 3.5)) = 21/31
D) Find E(X)...
Ok so here is what I have let me know if this looks better
Mean: .21
87(0)+8(1)+3(2)+1(4)+1(3)=21/100
STDev:
E[x^2]-[E[x]]^2
.45-(.21)^2=.4059
sqrt(.4059)
STDEVA: .637
So would it be .45/100%= .0045, which seems also wrong but makes sense. Since the .45 is the number of quarters in the "system" sorta say, and then we accounted for 100% of the population.
So what is throwing me off is I think my calculation of the mean is incorrect. Because more people has 0 quarters then say 2 quarters, the the mean should theoretically be less then 2 correct?
Homework Statement
Mind mean and STDev of number of quarters someone has on them at one time
0 - 87%
1 - 8%
2 - 3%
3- 1%
4 - 1%
The first time I did this I assumed a population but she said that was wrong and not what she was looking for.
Here was my new attempt:
x^2f(x)=
0(.87)
1(.08)
4(.03)...
10 Digits chose 5
10!/(5!(10-5)!)= 252
I thought of it as 10*9*8*7*6=30240
5^10=9765625 ways to choose numbers ( this doesn't account for repeats not being allowed)
Homework Statement
A password has numbers 0-9 in it. The password is 5 digits, repeats are not allowed, and order doesn't matter (I just have to have the correct 5 digit buttons depressed).
A. If I guess at the password, what is the probability that the box will open?
B. If I have completely...
Well technically with how the question is worded it the sample space is accounted for. I guess we we assume there is only 3 conditions of a cell phone it's not accounted for. If we assume they there could be another option that wasn't listed it does account for 100% of the cases.
Homework Statement
Give an factory of cell phones there is a .5 rejections, .2 repaired, and .2 acceptable. Does this follow the axioms of probability.
Homework Equations
Sample space = 1;
Probaby: 0 -1
P(AnB)=P(A)+P(B)
The Attempt at a Solution
Technically this does follow the axioms, there...
I do not think this would be a permutation because we could careless about the order right? We could have my friend would be app 3 and friend 2 be app 5. But they could hire app 2 5 3 9 etc.
12 nPr 4 = 11880
4! = 24
24/11880 = .002%
This would be: 12!/(12-4)! = .002% which could be right...
Homework Statement
Assume a job has 12 applicants, and 4 job openings. I want me and my 3 friends to all get the job. What is this probability.
Homework Equations
! Factorial and Permuation & combinatoins
The Attempt at a Solution
Number of possible solutions: 12C4 = 495 Possible ways
Number...
Homework Statement
Homework Equations
The Attempt at a Solution
1. I got Y(s) = (15s +18)/(5s^2+s-2)
2. I got Y(s) = (7s - 7iw + 1)/((s+4)(5 - iw))
Was just wanting to make sure I solved these right. I would type it out but without formating, it will look messy.