In mary's first math test she scored 87%. the mean and standard deviation for the class were 71% and 18% respectively. in her second math test, mary scored 66%. the mean and standard deviation for the class were 53% and 14% respectively. in which test did mary do better relative to the rest of the class? explain your reasoning. (hint: find the z-scores corresponding to her two test scores.)

Step-by-step explanation:

Since your population are the students in math class, you can use the z-score formula in order to comparing the two math test scores. Where is the mean for the class, is the standars deviation and x is Mary score.

For the first test , so ,.

For the second test , so ,

Mary do better in the second test, relative to the rest of the class (because  , it means the second score is nearer to the mean score of the class than the first one )  

option 1

data plot with   3 dots over 33, 1 dot over 34, 2 dots over 35, no dot over 36, 1 dot over 37, 2 dots over 38, 4 dots over 39, and 2 dot over 40.

a; x = 0.5

step-by-step explanation:

-10x = -5

x = 0.5