Use a table to find a z-score that fits the given conditions. Interpolate if necessary.

33% of the area under the standard normal curve is above the score.

Question

Use a table to find a z-score that fits the given conditions. Interpolate if necessary.

33% of the area under the standard normal curve is above the score.

anonymous · Answer

Make sure you check to see how the table you are using shows its areas. Most show areas to the left (below) the z-score. So you have to take the complement of any probability (area) given that is above the score. Complement = 1-p. 1-.33 = .67, so find the score for probability (in the body of the table) of 0.6700.

anonymous · Answer

you want the z-score corresponding to 67% area to the left of the z-score.  Now, 50% of the area is to the left of the mean, so you need the z-score that corresponds to an area of the curve from the mean to the z-score=17%.   From my table I get z=0.44

anonymous · Answer

By "interpolate" it means that you likely won't find 0.6700 exactly in the table, so find the two values that are closest and take the average of their z-scores.
*(Using the inverse-normal function on a calculator works well also..)

anonymous · Answer

fyi no need to interpolate on this one.  the z-score corresponding to an area of 0.6700 is on the table.