The burning time of a very large candle is normally distributed, with a mean of 2500 hours and a standard deviation of 20 hours. find the z-score that corresponds to a lifespan of 2470 hours. a. 2.5
b. 1.5
c. -1.5
d -2.5

Value of z-score is -1.5

Option C is correct.

Step-by-step explanation:

We are given

Mean = 2500 hrs

Standard Deviation = 20 hours

X = 2470

We need to find z-score

The formula used to calculate z-score is:

Putting values of x, mean and standard deviation in the formula

So, value of z-score is -1.5

Option C is correct.

step- i d k and i d c : )

you: : 0

bye

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