Question

Which is the joint relative frequency for school children who plan to attend camp and have swimming lessons? Round the answer to the nearest percent.
4%
19%
33%
44%

Answer 1

The answer is the last one 44%. 

Answer 2

Given a frequency table of a survey asking school children whether they are attending a summer camp, taking swimming lessons, or both.

                                                       Summer Plans
                                           Camp                      No Camp                  Total
Swimming Lessons               42                              32                          74

No Swimming Lessons         18                                4                           22

Total                                      60                               36                          96

The relative frequency table is obtained from the frequency table by dividing each entry of the frequency table by the overall total of the frequency table.

The relative frequency table of the above frequency tale is given below.

                                         Summer Plans (Relative Frequency)
                               Camp                      No Camp                  Total
Swimming
Lessons      42/96 = 0.44 = 44%    32/96 = 0.33 = 33%    74/96 = 0.77 = 77%

No Swimming
Lessons      18/96 = 0.19 = 19%    4/96 = 0.04 = 4%        22/96 = 0.23 = 23%

Total            60/96 = 0.63 = 63%    36/96 = 0.37 = 37%    96/96 = 1.0 = 100%

Therefore, the joint relative frequency for school children who plan to attend camp and have swimming lessons is 44%