Question

Refer to the accompanying table, which describes the number of adults in groups of five who reported sleepwalking. Find the mean and standard deviation for the numbers of sleepwalkers in groups of five.

The mean is _______  nothing sleepwalker(s). (Round to one decimal place as needed.) 

The standard deviation is _______  sleepwalker(s). (Round to one decimal place as needed.)

Answer 1

(a) Mean = 1.5

We know that:

Hence,

x	P(x)	x*P(x)
0	0.18	0
1	0.351	0.351
2	0.307	0.614
3	0.134	0.402
4	0.025	0.1
5	0.003	0.015
Mean		1.482

(b) S.D. = 0.5

x	P(x)	(x-mean)	(x-mean)^2	((x-mean)^2)*P(x)
0	0.18	-1.482	2.196	0.395
1	0.351	-0.482	0.232	0.082
2	0.307	0.518	0.268	0.082
3	0.134	1.518	2.304	0.309
4	0.025	2.518	6.340	0.159
5	0.003	3.518	12.376	0.037
SUM				1.064

Hence,

I hope this solves your doubt.

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