Find the z-score value corresponding if the location is below the mean by 2 standard deviations

If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what is the z score of a 3rd grader who is 47 inches tall?

Adam's Z-score on a test is +2.50. What does this mean?

Which of the following is a formula that describes calculating a z-score?

Scores on a certain standardized test have a mean of 500, and a standard deviation of 100. What score would you need to fall at the 84th percentile?

The Floppy Disk Company makes 3.5 inch floppy disks for disk drives that are 3.7 inches wide. The size of a manufactures disk is normally distributed with a standard deviation of 0.1 inches. The company manufactures 1000 disks every hour.

In one hour, how many disks would you expect to be between 3.4 inches and 3.7 inches?

Standard deviation tells us how spread out a symmetric distribution is. 
Since a Z-score tells us how many standard deviations away from average something is, what does a high Z-score mean?

Adam's Z-score on a test is +2.5.  What does this mean?

Joanne's Z-score is -1.5.  What does this mean?

Z-scores are calculated by subtracting the mean from the score and then dividing by the standard deviation.  Which of the following is a formula that describes this calculation?