Some psychologists believe that a genius should be defined as anyone having an iq over 140. if iq scores are normally distributed with a mean of 100 and a standard deviation of 17 and if the population of the world is 6,575,000,000, how many geniuses are there in the world today

61,239,550

Step-by-step explanation:

We let the random variable X denote the IQ scores. This would imply that X is normal with a mean of 100 and standard deviation of 17. We proceed to determine the probability that an individual chosen at random from the population would be a genius, that is;

Pr( X>140)

The next step is to evaluate the z-score associated with the IQ score of 140 by standardizing the random variable X;

The area to the right of 2.3529 will be the required probability. This area from the standard normal tables is 0.009314

From a population of 6,575,000,000 the number of geniuses would be;

6,575,000,000*0.009314 = 61,239,550

61,805,000

Step-by-step explanation:

lets assume, no of geniuses = X

P(X > 140) = P(z > (140 - 100)/17)

                = P(z > 40/17) ⇒ P(z > 2.352)

1 - P(z < 2.352) = 1 - 0.9906 ⇒ 0.0094

The number of geniuses in the world today are:

0.0094 x 6,575,000,000 = 61,805,000

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

answer: it is d

step-by-step explanation: