STAT 443 Survey Methods

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Questions and Answers

What is the primary focus of the STAT 443 module?

Quantitative design and analysis of household surveys (correct)

Basic principles of experimental design

Research methodology in non-statistical fields

Qualitative analysis of household surveys

Which of the following is NOT a prerequisite for the STAT 443 course?

Basic algebra

Introduction to statistics and probability

Advanced calculus (correct)

Research methodology

What percentage of the overall grade does the exam contribute to in STAT 443?

40%

50%

70% (correct)

30%

What is one of the objectives of the STAT 443 course?

To develop data handling skills for analysis Signup and view all the answers

Which statement correctly describes sample survey methods?

They deal with the principles of collecting data from finite populations. Signup and view all the answers

Which consequence results from late homework submission in STAT 443?

The homework will not be graded. Signup and view all the answers

In sample surveys, what do samples aim to achieve?

To reflect on the population they represent. Signup and view all the answers

What is a critical aspect of discussing survey data in this course?

Understanding both theoretical and practical considerations. Signup and view all the answers

What is the purpose of conducting a pre-test in a survey?

To identify potential problems on a smaller scale. Signup and view all the answers

Which of the following is NOT a principal step in conducting a survey?

Subjective emotional assessment Signup and view all the answers

What should be clarified regarding the handling of non-response in surveys?

Plans for dealing with absent respondents Signup and view all the answers

Why is it important to decide on estimation methods before starting a survey?

To have data compatible with chosen procedures. Signup and view all the answers

What data collection method involves the surveyor visiting the respondent personally?

Personal interview Signup and view all the answers

In a mail inquiry, what is typically included with the questionnaire to encourage responses?

A self-addressed envelope with postage. Signup and view all the answers

What is a critical factor to consider when analyzing data after a survey?

The relevance of chosen statistical tools. Signup and view all the answers

What is the main focus of organizing fieldwork for a survey?

Plans for executing the survey efficiently. Signup and view all the answers

What is assigned to each member of the population in a sampling frame?

Non-zero probability of being selected Signup and view all the answers

Which notation corresponds to the average of a sample?

Ȳ Signup and view all the answers

What does the symbol N represent in conventional notations?

Population size Signup and view all the answers

In a sampling mechanism, why are non-zero probabilities necessary?

To facilitate estimation and statistical inference Signup and view all the answers

What does the sampling method without replacement imply?

Once chosen, units are not placed back into the population Signup and view all the answers

Given the population P = {3, 5, 10, 14}, what is the population size (N)?

4 Signup and view all the answers

Which of the following statements about sampling with replacement is true?

Each unit can potentially be selected multiple times Signup and view all the answers

What is the primary purpose of specifying a sample size in probability sampling?

To define the scope of sampling Signup and view all the answers

Which method is considered the most basic form of probability sampling?

Simple random sampling Signup and view all the answers

What does systematic sampling aim to achieve?

Precision and subgroup certainty Signup and view all the answers

What is the definition of selection probability in sampling?

The chance a unit in the population is included in the sample Signup and view all the answers

What shows that selection probability does not need to be constant?

It can vary due to external factors Signup and view all the answers

When is it important to know or estimate the selection probability?

At the time of analysis Signup and view all the answers

Why might external factors jeopardize the integrity of a study?

They can influence the chance of inclusion in the sample Signup and view all the answers

What is the rationale behind stratification in sampling?

To increase precision of population estimates Signup and view all the answers

What is a finite population?

A collection of units like households and cities. Signup and view all the answers

What is the purpose of a sampling frame?

To provide a list of units to be surveyed. Signup and view all the answers

Which of the following is NOT a reason why sampling is preferred over complete enumeration?

Higher accuracy in findings. Signup and view all the answers

What characterizes a representative sample?

It reflects all salient features of the population. Signup and view all the answers

What is a static sampling frame?

A pre-existing complete list of population units. Signup and view all the answers

Which statement is true about the sampling unit in a survey?

It can consist of groups of elements as well. Signup and view all the answers

What is the main advantage of using sampling over a complete population census?

Lower costs associated with data collection. Signup and view all the answers

Which of the following is an example of a dynamic sampling frame?

All patients visiting a clinic during a defined period. Signup and view all the answers

What is the population total calculated for the given sample?

32 Signup and view all the answers

How many samples of size n = 2 can be formed when sampling with replacement from a population of size 4?

16 Signup and view all the answers

What is the population variance calculated from the given values?

24.6667 Signup and view all the answers

What is the mean of the given population values?

8 Signup and view all the answers

If each element in the population was to be doubled, how would the mean change?

It would increase to 16 Signup and view all the answers

In a sampling approach, what does sampling with replacement allow?

Repetition of the same value in multiple samples Signup and view all the answers

If the population were to increase in size but maintain the same total value, how would the mean be affected?

It would decrease Signup and view all the answers

Two variables are considered in relation to building blocks and dwellings. What is the relationship defined by?

Y is dependent on X Signup and view all the answers

Study Notes

Course Information

Course title: STAT 443: THEORY SAMPLING
Lecturer: Winnie M. Onsongo (PhD)
Department: Department of Statistics and Actuarial Science
University: University of Ghana
Email: [email protected]
Date: November 5, 2024

Prerequisites

Introduction to statistics and probability
Basic algebra
Research methodology

Assessment and Grading

Assignments + Interim Assessment (30%)
Exam (70%)
Homework submitted on time, late submissions not accepted
Duplicate solutions not graded

Course Objectives

Discuss theoretical and practical considerations of survey data
Discuss strategies for conducting preliminary analysis of large-scale, complex surveys
Develop data handling skills to prepare data for analysis

Introduction

Sample survey methods is a branch of statistics dealing with collecting and analyzing data from finite populations
This study covers suitable statistical principles and methods for collecting and analyzing data from finite populations
Society relies on data from surveys to describe the world and reflect the population it claims to represent
Quantitative data is essential to support arguments and discussions

Introduction Continued

Figures are essential to present data and understand situations clearly.
Those presenting statistical data have responsibility to present it fairly and objectively, including proper data sourcing, scope and methodology.

Sample Surveys and Opinion Polls

Finite populations have individuals with measures of interest
Exact characteristic values can be determined by studying each individual
Limited resources often require estimating characteristics by studying a smaller group (sample)
Data collected on individuals are often quantitative and factual, describing social or economic characteristics
Data is considered independent observations from a population following a probability model.
Surveys collected on humans can include views and preferences (opinion polls)
Sample surveys can aid market research for product qualities

Definitions

Finite population: A collection of units like households, people, cities or countries
Census: A complete count of all units in the population
Population: A collection of all sampling units in a region at a specific time or period
Sampling unit: An element or group on which observations are made (e.g., income of an individual in a household)
Representative sample: A sample reflecting all salient features of the population
Sampling frame: A list of all units in the population to be surveyed (e.g., university students with registration numbers)
Static/exhaustive list: A single list of all sample units existing before the study
Dynamic list: A list generated during the study of sample units. (e.g., patients visiting a doctor)

Why Sample?

Sampling allows a representative picture of a population without studying the entire population
There are several reasons for using statistical sampling rather than complete enumeration
Reduced cost: Expenditures are minimized when studying a portion of the population
Faster data collection and processing
Higher accuracy due to in-depth training for the personnel
Broader scope and flexibility in data collection

Types of Surveys

Demographic surveys (e.g., household surveys, family size, etc.)
Educational surveys (e.g., school attendance, graduation rates)
Economic surveys (e.g., industrial production, consumer spending, etc.)
Public polls and surveys (e.g., public opinion on specific issues)
Marketing surveys (e.g., consumer preferences, product needs, and impact on the market)

Principal Steps in a Survey

Define clear, understood survey objectives
Determine population for sampling (e.g., educational survey using students from basic school to senior high-school)
Identify necessary data related to survey objectives. Avoid unnecessary questions
Specify required degree of precision in data collection
Choose suitable measurement instrument and method (e.g., interview, questionnaires). Develop recording forms
Develop a comprehensive sampling frame
Select sample based on the sampling plan; determining cost and time of various sampling plans
Conduct a pre-test to address any problems before large-scale field work (e.g., test questionnaires and field methods)
Organize fieldwork adequately(e.g., handle non-response, address missing observations, training)
Summarize and analyze data (appropriate tools based on survey objectives, method of estimation, tolerable error limits)

Methods of Data Collection

Physical observations (e.g., personal contact; observing individuals, recording data)
Personal Interview (e.g., preparing standardized questionnaires for an interview)
Mail inquiry (e.g., well-made questionnaires mailed to respondents, self-addressed envelopes with postage)
Web-based inquiry (e.g., surveys on web pages; links sent via email)
Registration (e.g., data recorded at specified locations- births and deaths, family details)
Transcription from existing records (e.g., collection from existing data)

How to Sample

Goal: Create a fair representation of the population with high accuracy estimates
Various sampling methods exist (e.g., accessibility, haphazard)
Accessibility/haphazard sampling: Choosing the easiest to access observations (potential lack of representativeness)
Judgment sampling/purposive sampling: Surveyor intentionally picks individuals with good accessibility and representativeness

Quota Sampling

Highly structured method, defining how many individuals are needed in each quota
Main criticism of haphazard and judgmental sampling: lack of a clear basis for representativeness (no set guiding principles)

Central Concept of Probability Sampling

Population characteristics (e.g. total, mean, proportion falling into a category)
Estimating population characteristics from a sample of 'n' units

Probability Sampling

Specifying sample size 'n'
Identifying all potential samples of 'n' units drawn from the population
Defining probabilities for each sample
Using probabilistic methods to select the sample (e.g., Simple Random Sampling)

Probability Sampling Methods

Simple random sampling: Basic method, used for other probability sampling schemes
Systematic sampling: Enhancing precision and ensuring subgroup sampling
Stratification: Performing to enhance population-level estimates and facilitate estimates for sub-groups

Selection Probability

Probability of including a unit in the sample
Selection probability may not to be known initially; it is sufficient to know or estimate this during the analysis
External factors can affect this sampling

Notations

Table showing population and sample quantities (e.g., size, unit index, value, average, total)

Sampling from a Finite Population

Sampling mechanism: Assigning selection probabilities to population members
Two ways to obtain a sample
- Without replacement: Units not put back in the population
- With replacement: Units placed back in the population

Characteristics of the Population

Population average
Population variance
Population total

China Town

Example, Population (e.g the number of households, properties, businesses)
Variables of interest (e.g., number of buildings, dwellings).
Listing of various dwellings/units/elements in China Town (data)
Population totals (e.g. total number of blocks)
Population averages (e.g. average dwellings)
Population variances (e.g. Variance in number of dwelling/blocks)
Ratio (e.g. ratio of no. of dwelling to no. of blocks)
Proportion

Proportion

Proportion can be calculated as the average of a variable
Defined for lots (e.g., determining whether a lot is occupied or empty)

Population Quantities

Population covariance
Population correlation

Sampling Mechanisms

Assigning probabilities to all samples possible from a population for a given sample size

Sampling with Equal Probabilities

Mechanism to determine probabilities based on samples from a population
Two versions: -Without replacement (units only picked once) -With replacement (Units can be picked repeatedly)

Sample Quantities

Sample Fraction (Sample Size/Population Size)
Differentiating between population quantity
Sample quantity
Estimate

Some Observations

When is an estimator good?,
Expectation, Variance, Bias, Mean Square error

Thank You

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Description

Test your knowledge on the key concepts and prerequisites of the STAT 443 course, focusing on survey methods. This quiz covers objectives, grading criteria, and essential steps in conducting surveys, providing a comprehensive review for students. Ideal for those looking to reinforce their understanding of this important module.