QUESTION 1 (251
a) Discuss the following concepts as used in sampling theory
(i) Sampling design
[2]
(ii) Quota Sampling
(2)
(iii) Non-probability sampling
(2)
(iv) Snow ball
(2)
(v) Sampling error
[2)
b) Write a short notes on the concepts: Sampling error and Non-sampling error
[4)
c) Discuss why we use the sampling with replacement in sampling theory?
[SJ
d) Briefly discuss three principal reasons for using stratified random sampling rather
than simple random sampling
(6)
Question 2(251
2.1 To estimate the total number of students needed to work on a turn-around strategy, the
Registrar office subdivide the strategy into 100 equally sized units. The observed samples
are given below;
234,256,128,245,211,240,202,267
a) Estimate the population total
[4)
b) Estimate Var(y)
[6]
2.2 A farm has 1000 young pigs with a weight of about 50 lbs (1 pound=0.4Skg). They put
them on a new diet for 3 weeks (minimum weight is estimated to be lOlbs).
a) How many pigs should they sample to estimate the average weight gain, if they
want the answer to be within 2 lbs. with 90% confidence.
(15)
Question 3(501
3.1 NUST knows that 40% of its account receivable comes from student and 60% from
Government (subsidy). An auditor randomly sampled 100 accounts without replacement.
Here are the results of his sampling:
Students
n1 =70
5'1=520
S1=210
Government
n 2=30
5'2=280
S2=90
a) Compute the post-stratified mean and the variance of the post-stratified
(10)
SAMPLING THEORY (SAT802S)
l' t Opportunity November 2023 2