## Question 716:

1## Answer:

No answer provided yet.We can use the formula for the z-score for a datapoint to solve this one. The formula is (datapoint-mean)/standard deviation = z-score. Before we do this, we need to find the z-scores for the three proportions .80, .90 and .95 using a table of normal values for 1-sided area (or the excel function =NORMSINV() ).We get the z-scores of .841621, 1.28155 and 1.64485.

Now we substitute each of these into the z-score equation to solve for the unknown score.

- (data-point-mean)/standard deviation = z-score
- (data-point-90)/10= .841621
- data-point-90= 8.41621
- data-point= 98.41621