Which is the higher relative score: A score of 66 on a test with a mean of 80 and a standard deviation of 6, or a score of 70 on a test with a mean of 80 and a standard deviation of 3? Explain your choice. (Hint: Use z-scores).

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.