Calculate cumulative frequency and cumulative percentage

Question

Use the following data to answer parts a, b, c, and d below (assume continuous data).  Be sure to reproduce the frequency distribution and add columns for cumulative frequency and cumulative percentage.

                        Interval                       Frequency

                       90-99                                4

                         80-89                              7

                         70-79                            11

                         60-69                              9

                         50-59                              8

                         40-49                              7

                         30-39                              5

                         20-29                              3

                         10-19                              2

                           0-9                                1

                  a.   Compute the 88^th percentile.

                  b.   Compute the 33^rd percentile.

                  c.   Compute the percentile rank for a score of 45.

                  d.   Compute the percentile rank for a score of 90.