Question

Based on the information, please compute the following measures:

Daily Supply (y) Unit Price (x)

10 6

14 12

17 8

13 10

16 9

a) Standard deviation for variable y and for variable x

Answer 1

Standard Deviation:

It measures spread of the data about mean value.

It is denoted by .

Here, X = given variable

= mean

(i) Standard variation for variable y:

Step 1: Find :

n=5

=

So, = 14

Step 2 : Make table:

Y	Y-	(Y-)2
10	10-14=-4	(-4)2=16
14	14-14=0	0
17	17-14=3	9
13	13-14=-1	1
16	16-14=2	4
= 70

Step 3: Find Standard deviation

Here, n=5

(ii) Standard variation for variable X:

Step 1: Find :

n=5

=

So, = 9

Step 2 : Make table:

X	X-	(X-)2
6	6-9=-3	(-3)2=9
12	12-9=3	9
8	8-9=-1	1
10	10-9=1	1
9	9-9=0	0
= 45

Step 3: Find Standard deviation

Here, n=5