Page 165 - DMGT209_QUANTITATIVE_TECHNIQUES_II

Quantitative Techniques-II

Notes 
 
x
n
where  is the standard deviation of the population distribution of that quantity and n is the size
(number of items) in the sample.



Caselet Case of Food Manufacturer
leading, food manufacturer inserted a full-page advertisement in a Metro, offering
Aa double coupon deal i.e. the retail store will redeem the company coupon at twice
its face value to customers who shopped in Ahar between 8 a.m. to 9 p.m. the next day. A
random sample of 200 consumers on the following day of promotion produced the results
as below:

a. 100 of the 200 respondents had been to Ahar between 8 a.m. to 9 p.m.
b. Of these 100 respondents, 85 had seen the company’s full-page advertisement.
c. Of the remaining 100 respondents, who had not been to Ahar, only 50 had seen the
company’s ad.
On the basis of the above findings of the survey, the company claimed that, the promotion
was a “big success”. Do you agree? If so, explain why do you think so?

Self Assessment

Fill in the blanks:
13. Non-response error may be due to 1)………………, 2) flat refusal.
14. Sampling distribution is the probability distribution of a given statistic based on a
……………of certain size n.

8.8 Summary

 Sample is a representative of population.
 Census represents cent percent of population.

 The most important factors distinguishing whether to choose sample or census is cost and
time. There are seven steps involved in selecting the sample.
 There are two types of sample, namely, Probability sampling and Non-probability sample.

 Probability sampling includes random sampling, stratified random sampling systematic
sampling, cluster sampling, Multi-stage sampling.
 Random sampling can be chosen by Lottery method or using random number table.

 Samples can be chosen either with equal probability or varying probability.
 Random sampling can be systematic or stratified.
 In systematic random sampling, only the first number is randomly selected.
 Then by adding a constant “K” remaining numbers are generated.

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