How large a sample size is needed to estimate the mean annual income of people in a certain county, correct to within $1300 with probability 0.99? no information is available about the standard deviation of their income. it is estimated that nearly all of the incomes fall between $0 and $180 , 000 and that this distribution is approximately bell-shaped.

you'll just earn points here

step-by-step explanation:

where's the diagram?

step-by-step explanation:

the polynomial is a perfect square trinomial of the form a^2-2ab+b^2:

option a. true

step-by-step explanation:

9x^2-12x+4

comparing with the form a^2-2ab+b^2

1.) a^2=9x^2

solving for a: square root both sides of the equation:

sqrt(a^2)=sqrt(9x^2)

a=sqrt(9) sqrt(x^2)

a=3x

2.) b^2=4

solving for b: square root both sides of the equation:

sqrt(b^2)=sqrt(4)

b=2

to be a perfet square trinomial 2ab must be equal to 12x. let's check:

2ab = 2 (3x) (2)

2ab = 12x

correct