I need help understanding Statistics. Not looking for answers, only guidance.

Question

I am having a hard time understanding how to compare z scores to the critical values. I already used Minitab Express to find the z scores. Could someone please explain how I can go about finding the answers using the ages and heights of the subjects I created? 

Assignment: 

Using the z-score of ±1.645 for the 5 percent cutoff and the z-score of ±1.96 for the 2.5 percent in the tail, identify the subject identification (ID) number for subjects who are closest to the cutoff for the upper 2.5 percent and 5 percent of the scores and the lower 2.5 percent and 5 percent of the scores. Do this by comparing each participant’s z-score with the appropriate critical value (1.645, 1.96, -1.645, -1.96).

Answer 1

z = (x - mean)/ stdev

z * stddev + mean = x

so you will calculate

1.65*stdddev + mean and see whose scores are closest to that

then you do

1.96*stddev + mean

and see who is closest to that