Classes Limits	frequency	d
39.9 42.8	2	-2
42.9 45.8	2	-1
45.9 48.8	5	0
48.9 51.8	5	1
51.9 54.8	12	2
54.9 57.8	5	3
Total

(Please show step by step solution so I can easily understand thank you)

Answer the below question using D method

a.) Mean

b.) Median

c.) Mode

d.) Range

e.) Variance

f.) Standard deviation

g.) 90th percentile