Question

Given the data set: 72.51, 72.61, 73.67, 72.55, identify/calculate:

a) the suspected outlier

b) the absolute value of “suspect value – average value”

c) the absolute standard deviation

d) G calculated

e) G _reference

f) May we reject the suspect value?

Answer 1

(a)

The suspected outlier = 73.67

Explanation:

From the given data, the following statistics are calculated:

n = Sample Size = 4

= Sample Mean = 291.34/4 = 72.835

The deviations of 4 data points from mean are as follows:

x	(x - )
72.51	- 0.325
72.61	- 0.225
73.67	0.835
72.55	- 0.285

It is noted that the point 73.67 has the maximum deviation. So,it is the suspected outlier.

(b)

The absolute value of "suspect value - average value" is given by:

(c)

x	(x - )	(x - )2
72.51	- 0.325	0.1056
72.61	- 0.225	0.0506
73.67	0.835	0.6972
72.55	- 0.285	0.0812
Total =		0.9347

Variance = s² =0.9347/3 = 0.3116

So,

the absolute Standard Deviation = s =

(d)

(e)

For n = 4, From Table:

(f)

Since :

We cannot reject the suspect value.