Answer: C . 
and 
Step-by-step explanation:
Definition:
Null hypothesis
is a statement about the population parameter according to the objective raised by the researcher . It contains '=' , '≤' and '≥' signs.
Alternative hypothesis
is also a statement about the population parameter but against null hypothesis . It contains '≠' , '<' and '>' signs.
Let 
be the average customer waiting time for the population.
Given : The average customer waiting time at a fast food restaurant has been 7.5 minutes.
Objective of test : After using new system , the average customer waiting time is at least 7.5 or less than 7.5.
Then, the null and alternative hypothesis for this scenario will be :
Hello
<span>3 2/3 \ 3 2/9
(32/3) × (9/32) = 9/3=3</span>
<span>3. Two isosceles right triangles
Every square has 4 right angles, so each triangle will have one right triangle, which makes the triangles, right triangles.
They are isosceles because all sides of the square are the same, though the diagonal is not.
Hope this helps :)
</span>
Answer:
A. E(x) = 1/n×n(n+1)/2
B. E(x²) = 1/n
Step-by-step explanation:
The n candidates for a job have been ranked 1,2,3....n. Let x be the rank of a randomly selected candidate. Therefore, the PMF of X is given as
P(x) = {1/n, x = 1,2...n}
Therefore,
Expectation of X
E(x) = summation {xP(×)}
= summation {X×1/n}
= 1/n summation{x}
= 1/n×n(n+1)/2
= n+1/2
Thus, E(x) = 1/n×n(n+1)/2
Value of E(x²)
E(x²) = summation {x²P(×)}
= summation{x²×1/n}
= 1/n
