Statistics and Probability Problems

[SHOSHO19]

1)X=0,1,2,3,4

FIND E(X)

The attempt at a solution:

E(X)= (4 X)(.4)X (,6)4-X



2) YOU CAN TOSS A FAIR COIN UP TO 7 TIMES.YOU WILL WIN 1000$ IF THERE TAILS APPEAR BEFORE A HEAD IS ENCOUNTERED. WHAT ARE YOU CHANCES OF WINING ?


The attempt at a solution:
2*2*2*2*2*2*2=128


3)In a study to correlate senior year high school students scores in mathematics and enrollment in engineering colleges a 1000 students were surveyed:
400 have studied mathematics
Engineering enrollment shows that of the 1000 seniors:
150 have studied mathematics
29 have not
Determine the probability of:
a-A student who studied mathematics is enrolled in engineering
b-A student who neither studies mathematics nor enrolled in engineering
c-A student is not studying engineering

I do not understand it =(



4) Graduating high school seniors with an ACT score of at least 26 can apply to two universities A, and B, for admission. The probability of being accepted in A is 0.4 and in B is 0.25. The chance of being accepted in both universities is only 15%
a-Determine the probability that the student is accepted in B given that A has granted admission as well
b-is the probability that admission will be granted in A given that the student was accepted in B?


I do not understand it =(


I have 9 homeworks
I worked 5 and left 4 and I ask you to help me =(

 

[SHOSHO19]

Up :(

 

[lanedance]

happy to help, but you need to attempt some work.. what have you tried

also, please try and write down your questions just as they are given, or be vry clear, they are quite difficult to follow