LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – STATISTICS
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THIRD SEMESTER – November 2008
ST 3502 / 4500 – BASIC SAMPLING THEORY
Date : 08-11-08 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART A
Answer ALL the Questions. (10 x 2 =20)
- Define the term “statistic” in finite population sampling.
- What do you mean by probability sampling?
- What will happen to the variance of sample mean under simple random sampling without replacement, if the sample size is increased?
- Mention an unbiased estimator of in simple random sampling without replacement where is the sample mean.
- Under what condition PPSWR reduces to SRSWR?
- Give an unbiased estimator of the population total in PPSWR, when the sample size is one.
- What is meant by Neyman allocation?
- Under what condition Neyman allocation reduces to Proportional allocation?
- Write all possible Circular systematic samples of size 3 when the population size is 7.
- Write the down the model used for representing populations exhibiting linear trend in Sampling Theory
PART B
Answer any FIVE Questions. (5 x 8 =40)
- Compare Sampling with Census.
- Illustrate with an example thatUnbiasedness is a sampling design dependent property.
- Derive under simple random sampling without replacement.
- Define Hansen – Hurwitz estimator and obtain its variance under PPSWR.
- Show that Lahiri’s method of sample selection is a PPS selection method.
- Derive the formula for Optimum allocation for fixed variance in stratified random sampling.
- Explain Balanced systematic sampling and derive the under BSS assuming the population values possess linear trend
- Derive the condition under which LSS is more efficient than SRS in terms of
PART C
Answer any TWO Questions. (2 x 20 =40)
- (a) Bring out the relationship between Mean Square Error, Bias and Variance of an estimator
(b) Show that is unbiased for in SRSWOR
- Assume that there are two strata with and relative weights and . Show that for the given cost , . Assume the strata sizes are large.
- Derive the Yates corrected estimator under Linear Systematic Sampling for populations possessing linear trend.
- Write short notes on the following
- Cumulative Total Method
- Modified Systematic Sampling
- Proportional allocation
- Limitations of Systematic Sampling
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