8. it has been estimated that about 18.5% of adults whose income is below the poverty level work full-time throughout the year. a random sample of 150m people whose poverty level meets the criteria have been chosen

a. what is the expected value?

b. calculate the standard deviation

The expected value is 27.75 million and standard deviation is 81.5%

Explanation:

Given the sample was selected from the population

The population was of 150 million people

(a) Expected Value

Given that the adults whose income is below poverty line is 18.5%

Expected value = 18.5% of 150 million

=

= 27.75 million

Therefore, the expected value is 27.75 million

(b) Standard deviation

Standard deviation =  

Standard deviation is 81.5%

x -

median = 1.25

range = 12-14.5

interquartile = q12-q14.5

y -

median = 1

range = 15-17

interquartile = q15-q17

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3