z-Score

For this assignment, use the data you created in your W1 Midweek Assignment.

Using Microsoft Excel and following the instructions given in your lecture, convert each subject’s age and height into a z-score.

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 fall at or above the cutoff for the upper 2.5 percent and 5 percent of the scores and those who are at or below the lower 2.5 percent and 5 percent of the scores. Do this by comparing each participants z-score with the appropriate critical value (1.645, 1.96, -1.645, -1.96).

To fall into the upper tail of 5% (the 95th percentile), a participants z-score would need to be equal to or greater than 1.645. To fall into the upper tail of 2.5% (the 97.5th percentile), the z-score would need to be equal to or greater than 1.96. For the tails at the lower end, you would look for z-scores of -1.645 or lower (5%) or -1.96 or lower (2.5%)

Using the following table, identify the subject ID numbers in the tails for the appropriate cutoffs in an APA formatted Microsoft Word document.

Age

Height

Upper Extremes

Lower Extremes

Upper Extremes

Lower Extremes

5%

2.50%

5%

2.50%

5%

2.50%

5%

2.50%

z =        1.645    or higher

z =        1.96       or higher

z=            -1.645    or lower

z=            -1.96    or lower

z =        1.645    or higher

z =        1.96       or higher

z=            -1.645    or lower

z=            -1.96    or lower

Participant IDs for those with z-scores that fall into these extremes go in the boxes below