A certain mental development index for infants is a standardized measure used in observing infants over time. It is approximately normal with a mean of 99 and a standard deviation of 19. Find the z-score corresponding to the upper quartile (Q3) of a normal distribution.

0.67449

Step-by-step explanation:

Let be the  3rd quartile of normal distribution  .

-z-score corresponding to the upper quartile can be calculated in excel as:

-The output is 0.67449. Hence, the z-score corresponding to the upper quartile (Q3) of a normal distribution is 0.67499

step-by-step explanation:

bob the banana

x² + 3x + 7 = 0       [ax² + bx + c]

a = 1

b = 3

c = 7

quadratic formula:

    (+/- is this ±)

plug in the numbers into the variables

your answer is a