Given: and Prove: slope of × slope of = -1 Statements Reasons 1. is similar to Given 2. Property of similar triangles 3. slope of slope of Definition of slope 4. slope of slope of Multiplying the slopes 5. slope of slope of Substitution property of equality 6. slope of slope of = -1 Simplifying the right side The table shows the proof of the relationship between the slopes of two perpendicular lines. What is the missing statement in step 2? A. B. C. D.

a

step-by-step explanation:

irst, find the z score of a score of 80. this is given by the formula z = (x-u)/o, where x is the score, u is the mean, and o is the standard deviation. this gives

z = (80-78)/12 = 1/6 = .1667

now, find what percentile a z score of 1/6 correlates to in the normal distribution.

a z score of 1/6 = .1667 is equivalent to the 56.36th percentile of the distribution. so the probability a score is over this is 1-.5636 = .4364

the mean of a sample mean is equal to the original mean. however, the standard deviation of a sample mean is equal to the original standard deviation divided by the square root of n (sample size). so the new standard deviation is 12/sqrt(16) = 3.

the new z score is 80-78/3 = 2/3 = .667. this is equivalent to the 74.86th percentile. so the probability that the mean will be greater than this score is 1-.7486 = .2514.