Pak Study® Library  
Forum  
1. Attempt any SIX parts:  6  

i)  What do you mean by CLUSTER SAMPLING?  
ii)  Explain the Difference between CENSUS and SAMPLING.  
iii)  Write the Two Plause Points of SAMPLING.  
iv)  When we say that Estimator is to be Unbiased?  
v)  Write any Four Properties of tDISTRIBUTION.  
vi)  What is meant by 1 – á, Explain it?  
vii)  What is meant by ONETAILED TEST?  
viii)  Discuss the Difference between CHISQUARE DISTRIBUTION and tDISTRIBUTION.  
ix)  When the FDistribution tends to normal?  
SECTION – B  
2. a) Draw with the help of random numbers, a random sample of size 10 from a binomial distribution with  
parameters P = 0.4 and n = 5. b) Suppose a population of N = 9 is Stratified into 3 Strata with the following measurements.  3  
Stratum – I = 2, 3, 4 StratumII = 3, 6 StratumIII = 1, 2, 3. If two measurements are drawn from each  
stratum for the sample, List these samples and compute the mean for each sample.  5 
b) Find a 99% confidence interval for the mean of a normal distribution with ó = 2.5 and if the sample of size 7 gave the values 9, 16,10,14,13 and 14. What would be the confidence interval if ó was unknown? 4
(Continued Overleaf)
6. a) In a random sample of 1000 houses in a certain city 618 own colour TV Sets. Is this sufficient evidence
to conclude that 2/3 of the houses in this city have Colour TV Sets? Use á = 0.02. 4 b) It has been found from experience that the mean breaking strength of a particular brand of thread is
9.63 N with a standard deviation of 1.04N. Recently a sample of 36 pieces of thread showed a mean breaking strength of 8.93N. Can we conclude at 5% and 6% level of significance that thread has become inferior? 4
7. a) A manufacturer claims that the average life of his light bulbs is 2000 hours. A random sample of 64

bulbs is tested and the life of X hours is recorded. The results are; Óx = 127808 and Ó(x x )^{2 }= 9694.6. Test the hypothesis at 1% level of significance that the manufacturer is over estimating the length of life of his bulbs. Assume that the distribution of life of bulbs is normal. 4
b) The means of simple sample of 500 and 400 are 11.9 and 10.9 respectively. Can the samples be regarded as drawn from a population of standard deviation 5? 4
8. a) A training instructor claims that has training methods are so efficient that the variance of the time requires by his trainees to complete a job does not exceed 30 seconds. If a random sample of 21 traineesyielded a variance of 33 seconds, do you think this evidence supported the instructor’s claim? 4

b) If the sum of squared deviations Ó(x x )^{2 }is 2.45 and the sample size is n = 20. Find a 98% confidence interval for the population standard deviation ó. 4
_{***}B.A/B.ScII (10/A) – xiii _{*** }
Thank you very much for your arrival 
last updated on 28042019 