Answer: A
Step-by-step explanation: when Constructing a confidence interval, it is important to take note of the margin of error which is given by the formulae below
Margin of error = critical value × σ/√n.
Where n is the sample size.
As we can see that the critical value is a constant and the population standard deviation.
Hence there is an inverse relationship between margin of error and sample size, which implies that a large sample size produces a small margin of error.
If the margin of error is small, it means the sample size will increase the like hood that the sample is a good representation of the population.
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
In this equation you can eliminate the x value
multiply the second equation by -2 and you get:
-2x - 2y = -10
when you add the two equations the x factors will cancel
2x + 3y = 6
- 2x - 2y = -10
---------------------
y = 16
you can find the x value by plugging the y value that you now know into one of the equations that you started off with.
To find an average you take the numbers to be averaged and add them together then You take the number and divide it by the number of numbers, in this case 4, and that gives you the average.
on this problem you want to do the opposite. you know the average she wants, an 87, so you multiply it by 4. 87*4=348. then you add the three numbers you have (88,81 and 87) and you get 256.
then you subtract 256 from 348 and you get 92. 92 is your answer to check just add 87+81+88+92=348
348/4=87
87 was the average she wanted.
Hope this helped! good luck :)
Answer:
(p -3q )(p -3q )
Step-by-step explanation:
p'2 - 6pq + 9q'2
(p -3q )(p -3q )
find two values that add to give 6 and multiply to 9
p x p =p'2
-3q x p = -3pq -3 x pq = -3pq ...... -3pq - 3pq = -6pq
-3q x - 3q = 9q'2
