The answer to the question
Total numbers=10
mean(average)=14.8
standard deviation=3.4254
variance_standard deviation)=11.73333
population standard deviation=3.24962
variance(population standard deviation)=10.56
1.25 - 0.5 = 0.75
1.25 hours = 1 hour 15 minutes
0.5 hours = 30 minutes
1 hour 15 minutes - 30 minutes = 45 minutes