The following data provided are the average hours fifty-six grade 8 students spent doing their homework every school week last school year 2020-2021. The lowest number of hours recorded is 5 hours (every 5 school days), and the highest is 34 hours. The table's class interval is 5, and the mean is 18.9

HOURS	FREQUENCY
5-9	3
10-14	8
15-19	23
20-24	11
25-29	9
20-24	2

1. Find the range
2. Find the variance and standard deviation