In 503 exam, the scores obtained were later grouped into classes. Using an assumed mean of 38, calculate the: (i) Mean (ii) Median (iii) Standard deviation (iv) Interpret the students performance (v)

Okay faith, let's break down Question 1(a) from your assignment.

Question 1(a): In 503 exam, the scores obtained were later grouped into classes as follows:

Class Interval	16-20	21-25	26-30	31-35	36-40	41-45	46-50	51-55	56-60
Frequency (f)	3	4	5	8	12	9	6	2	1

Using an assumed mean of 38, calculate the: (i) Mean (ii) Median (iii) Standard deviation (iv) Interpret the students performance (v) When is median preferred to mean as a performance indicator?

First, let's set up a table to calculate midpoints ($x$), deviations ($d = x - A$), $fd$, $d^2$, and $fd^2$.
Assumed Mean ($A$) = 38
Class width ($i$) = 5

Class Interval	f	x (midpoint)	d = x - 38	fd	$d^2$	$fd^2$	cf
16-20	3	18	-20	-60	400	1200	3
21-25	4	23	-15	-60	225	900	7
26-30	5	28	-10	-50	100	500	12
31-35	8	33	-5	-40	25	200	20
36-40	12	38	0	0	0	0	32
41-45	9	43	5	45	25	225	41
46-50	6	48	10	60	100	600	47
51-55	2	53	15	30	225	450	49
56-60	1	58	20	20	400	400	50
Total	N=50			-15		4475