121
3)
4)
14.9. ASSIGNMENTS
1)
Use the sign test to see if there is a difference between the number of days
required to collect an account receivable before and after a new collection
policy. Use the 0.05 significance level.
Before : 33 36 41 32 39 47 34 29 32 34 40 42
After : 35 29 38 34 37 47 36 32 30 34 41 38
2)
A sequence of small glass sculptures was inspected for shipping damage. The
sequence of acceptable and damaged pieces was follows
D,A,A,A,A,D,D,D,D,D,A,A,D,D,A,A,A,A,D,A,A,D,D,D,D
Test for the randomness of the damage to the shipment using 0.05
significance level.
3)
Given the following Ten paired sample observations
X 42.7 50.4 44.2 49.7 49.4 55.3 46.1 49.8 48.7 45.9
Y 54.2 43.7 34.0 46.1 55.4 58.2 53.4 43.6 57.0 61.9
Test the hypotheses that the two samples have come from identical
population by using sign test.
4)
On testing a coin 15 times, the following sequence of heads (H) and tails (T)
was obtained
TT HHH T H T HHH TT HH
Test whether the coin is unbiased by the Run test.
14.10. REFERENCE BOOKS
1)
Agarwal, B.L., ‘Basic Statistics’, Wiley Eastern Ltd, New Delhi, 2
nd
ed., 1991
2)
Gibbon.
JD., “Non
-Parametric Statistical Inference
” Mc
Graw Hill Kogakusha
Ltd, Tokyo.
3)
S.C. Gupta and V.K.
Kapoor “Fundamental of
Mathematical Statistics
”
, Sultan
Chand & Sons.
14.11. LEARNING ACTIVITIES
Non-parametric tests are very convenient when the real world presents
distribution-free data on which a decision must be taken. But the sign test is just
another applications of the familiar normal approximation to the binomial using +
and
–
instead of success and failure. Run tests can often be useful in quality
management situations where we are trying to separate out systematic variation
from random variation. Systematic variation can cause the kinds of patterns that
runs tests detect.
14.12. KEY WORDS
1)
Paired data
2)
Randomness
3)
Identical occurrences
4)
Theory of runs
5)
Continuous variable.