MAT 4379-5192 Assignment 2 Fall 2023
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Assignment 2
MAT 4379-5192
Fall 2023
To hand-in on
September 27, 2023 on Brightspace before midnight
(pdf format only)
Problem 1
Consider a finite population U of size N = 5. We consider the following sampling design:
s |
{1, 2} |
{3,4} |
{3, 5} |
{4, 5} |
p(s) |
1/2 |
1/6 |
1/6 |
1/6 |
Table 1: The sampling design
(i) Determine the first-order inclusion probabilities.
(ii) Determine the second-order inclusion probabilities.
(iii) Does this sampling design correspond to simple random sampling without replace-
ment? Systematic sampling? Bernoulli sampling? Justify your answers.
Problem 2
Let S be a sample selected by a Bernoulli design with probability π . Let ns be the
random size of S. Show that
P(S = s | ns = n0 ) = .
That is, the conditional probability of S given ns is the same as the probability of a
simple random sample without replacement of the fixed size n0 from N.
Problem 3
Show the following properties for a fixed-size sampling design:
(i) πij = (n − 1)πi , for all i ∈ U;
Hint: Use the fact that Zi Zj = (n − 1)Zi.
(ii) πij = n(n − 1);
(iii) ∆ij = 0, for all i ∈ U, and ∆ij = 0, for all j ∈ U, where ∆ij = πij − πi πj .
Problem 4 (For graduate students only)
Let U be a population of size N. From U, we first select a simple random sample without replacement, S1 , of size n1 . Then, from S1 , we select a simple random sample without replacement, S2 , of size n2 . Show that S2 is a simple random sample without replacement of size n2 selected from U.
2023-10-21