DEFINITION of 'Stratified Random Sampling'
A method of sampling that involves the division of a population into smaller groups known as strata. In stratified random sampling, the strata are formed based on members' shared attributes or characteristics. A random sample from each stratum is taken in a number proportional to the stratum's size when compared to the population. These subsets of the strata are then pooled to form a random sample.
BREAKING DOWN 'Stratified Random Sampling'
The main advantage with stratified sampling is how it captures key population characteristics in the sample. Similar to a weighted average, this method of sampling produces characteristics in the sample that are proportional to the overall population. Stratified sampling works well for populations with a variety of attributes, but is otherwise ineffective, as subgroups cannot be formed.

Representative Sample
A subset of a statistical population that accurately reflects ... 
Durbin Watson Statistic
A number that tests for autocorrelation in the residuals from ... 
Population
The entire pool from which a statistical sample is drawn. The ... 
Sampling Error
A statistical error to which an analyst exposes a model simply ... 
Attribute Bias
The tendency of stocks selected by a quantitative technique or ... 
Weighted Average
An average in which each quantity to be averaged is assigned ...

Options & Futures
An Introduction To Value at Risk (VAR)
Volatility is not the only way to measure risk. Learn about the "new science of risk management". 
Investing
How to Use Stratified Random Sampling
Stratified random sampling is a technique best used with a sample population easily broken into distinct subgroups. Samples are then taken from each subgroup based on the ratio of the subgroup’s ... 
Markets
The Uses And Limits Of Volatility
Check out how the assumptions of theoretical risk models compare to actual market performance. 
Bonds & Fixed Income
Find The Highest Returns With The Sharpe Ratio
Learn how to follow the efficient frontier to increase your chances of successful investing. 
Active Trading Fundamentals
How To Convert Value At Risk To Different Time Periods
Volatility is not the only way to measure risk. Learn about the "new science of risk management". 
Active Trading
Modern Portfolio Theory: Why It's Still Hip
See why investors today still follow this old set of principles that reduce risk and increase returns through diversification. 
Options & Futures
Financial Concepts
Diversification? Optimal portfolio theory? Read this tutorial and these and other financial concepts will be made clear. 
Markets
The (Expected) Market Impact of the 2016 Election
With primary season upon us, investor attention is beginning to turn to the upcoming U.S. presidential election. 
Term
How Statistical Significance is Determined
If something is statistically significant, it’s unlikely that it happened by chance. 
Economics
3 Charts All Investors Should See
Given the abysmal start to the year, the defining question is whether this is another painful but temporary correction, or the start of a bear market.

How does stratified random sampling influence government policy decisions?
Governments use various analytical techniques to examine the potential costs and benefits of policy options. One of those ... Read Full Answer >> 
How can I use systematic sampling with stratified sampling?
Statistics offers different sampling methods for dealing with large populations; two common methods are systematic sampling ... Read Full Answer >> 
What are the best selection methods for creating a simple random sample?
The best selection methods for selecting a simple random sample are the lottery method, using a random number table or having ... Read Full Answer >> 
What are the advantages and disadvantages of stratified random sampling?
Researchers use stratified random sampling to obtain a sample population that best represents the entire population being ... Read Full Answer >> 
What are some examples of stratified random sampling?
Simple random sampling is a sample of individuals that exist in a population; the individuals are randomly selected from ... Read Full Answer >> 
Do plane tickets get cheaper closer to the date of departure?
The price of flights usually increases one month prior to the date of departure. Flights are usually cheapest between three ... Read Full Answer >>