Find the associated zscore or scores that represent the following standard normal areas. (Hint: Use the Excel function =NORM.S.INV to nd the zscore.) a. Middle 50 percent. (Negative values should be indicated by a minus sign. Round your answers to 4 decimal places.} z-score with lower tail z-score with upper tail b. Lowest 5 percent. (Negative values should be indicated by a minus sign. Round your answer to 4 decimal places} z-score c. Middle 90 percent. (Negative values should be indicated by a minus sign. Round your answers to 4 decimal places.) z-score with lower tail 7 z-rnrn tuith nnnnnn tail