Q.
1. ‘Statistics can prove anything’
‘Figures cannot lie’
Comment on the above two statements, indicating reasons for the existence of such divergent views regarding the nature and functions of statistics.
2. From the following data compute quartile deviation and the coefficient of skewness:
Size 5 – 7 8 – 10 11 – 13 14 – 16 17 – 19
Frequency 14 24 38 20 4
3. A bank has a test designed to establish the credit rating of a loan applicant. Of the persons, who default (D), 90% fail the test (F). Of the persons, who will repay the bank (ND), 5% fail the test. Furthermore, it is given that 4% of the population is not worthy of credit; i.e., P(D) = .04. Given that someone failed the test, what is the probability that he actually will default (When given a loan)?
4. Strength tests carried out on samples of two yarns spun to the same count gave the following results:
Number in
sample Sample
Mean Sample
variance
Yarn A 4 50 42
Yarn B 9 42 56
The strengths are expressed in pounds. Does the difference in mean strengths indicate a real difference in the mean strengths of the yarn?
5. Write short notes on
a) One-tail & two-tail tests
b) Standard normal distribution
c) Baye’s Theorem
