Answer:
Step-by-step explanation:
We define X the random variable that represent the heights of a population for ten year old children, and for this case we know the distribution for X is given by:
Where 
and 
We want to find this probability:
We can use the z score formula to solve this problem given by:
Using this formula we have:
And we can find this probability with this difference
We can use tables for the normal standard distribution, excel or a calculator and we got this
Answer: 7. 5/4
8. 1/3
Step-by-step explanation:
Answer:
A. The E(Y) is 0.80
B. The expected amount of the surcharges is $165
Step-by-step explanation:
A. In order to calculate the E(Y), we would have to calculate the following formula:
E(Y)=∑yp(y)
E(Y)=(0*0.5)+(1*0.25)+(2*0.20)+(3*0.05)
E(Y)=0+0.25+0.40+0.15
E(Y)=0.80
B. In order to calculate the expected amount of the surcharges we would have to calculate the following formula:
E($110Y∧2)=110E(Y∧2)
=110∑y∧2p(y)
=110((0∧2*0.5)+(1∧2*0.25)+(2∧2*0.20)+(3∧2*0.05))
110(0+0.25+0.80+0.45)
=$165
Answer: 4
Step-by-step explanation: 1) You need to first understand the question and a way to do that is to list plainly the information given.
2) Let the number be (X)
3) For the equation from the first sentence given; 3(9x-1)
4) From the second sentence; 7(7+2x)
5) Equating both sentences together, since the question says they are the same 3(9x-1) = 7(7+2x)
6) Opening the bracket/expanding the equation.... 27x-3=49+14x
Solving further we will have 13x = 52
X= 52/13
= 4
The answer is B.
There are about 391,000 of plants currently known to science.
Hope this helps.
