The data below shows the temperature of the water in a swimming pool over a two week period.
Week 1
Day Temperature (°F)
Monday 58
Tuesday 48
Wednesday 49
Thursday 61
Friday 58
Saturday 51
Sunday 39
Week 2
Day Temperature (°F)
Monday 68
Tuesday 74
Wednesday 73
Thursday 75
Friday 70
Saturday 67
Sunday 63
How many degrees greater is the mean temperature in week 2 than in week 1?