Question

Use the scenario and chart below to answer the following two questions. Twenty-five randomly selected students were asked the number of movies they watched the previous week. The results are as follows: #of movies of movies Frequency TL 3 4 Find the sample mean arx Find the approximate sample standard deviation, s

Answer 1

We have to find the sample mean.

Formula is

Mean - Στ * f Σ

	x	f	x*f
	0	5	0
	1	9	9
	2	6	12
	3	4	12
	4	1	4
Total		25	37

Σε * f 37 Mean = = Σ' = 25 = 1.48

Now we have to find the sample standard deviation, s.

3 z(2 - x) * =s 3

	x	f	(x-xbar)	(x-xbar)^2	f*(x-xbar)^2
	0	5	-1.48	2.1904	10.952
	1	9	-0.48	0.2304	2.0736
	2	6	0.52	0.2704	1.6224
	3	4	1.52	2.3104	9.2416
	4	1	2.52	6.3504	6.3504
Total		25			30.24

8 = Σf * (x – )2 4" 30.24 ") Σή = 25 . = V1.2096 = 1.0998