If ADEF - ADRS, find the value of x. Show Your Work
2x + 2
15
'S
D 10
12
value of x

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.

the correct answer is b.

this is because an open circle means < or > & since the line goes left it is < -3.

the next one has a filled circle so it can only be ≥ or ≤ and since the line goes right from 1 it is ≥ 1

hope that

answer is  

a.

16.1

hope you got it chief.