The following table shows the ages (in years) of a sample of 1,350 people who suffered accidents at home and who visited a certain health care center.

Age (years) N of people

[0 - 10[ 253

[10 - 20[ 189

[20 - 30[ 305

[30 - 40[ 136

[40 - 50[ 118

[50 - 60[ 115

[60 - 70[ 234

a) Calculate the average age of the people in this sample.

b) Calculate and interpret the median