Question

1. Repeated analyses yielded the following set of results:
19.7, 19.0, 18.8, 19.1, 18.9, 18.7.
Compute the Grubbs statistic for these data with respect to the potential outlier, 19.7.

G_calculated = ____________

2. Choose the statement which is a correct interpretation of the above result.
a) 19.7 can be rejected with greater than 95% confidence.

OR

b) 19.7 has more than a 5% chance of being a member of the same population as the other measurements.

Answer 1

Solution1:

grubbs test helps to identify outliers.

G=(given outlier-sample mean)sample sd

For given sample mean=19.03333
and standard deviation=0.3559026

G=19.7-19.03333/0.3559026

G= 0.6667/0.3559026

G=1.873265

Gcalculated =1.873265

ANSWER:

Gcalculated =1.873265

Solution2:

For n=6 G critical=1.822 at 95% confidence level

G cal >G critical,you can throw the data point

a) 19.7 can be rejected with greater than 95% confidence.

ANSWER:

a) 19.7 can be rejected with greater than 95% confidence.