DEFINITION of 'TTest'
A statistical examination of two population means. A twosample ttest examines whether two samples are different and is commonly used when the variances of two normal distributions are unknown and when an experiment uses a small sample size. For example, a ttest could be used to compare the average floor routine score of the U.S. women's Olympic gymnastic team to the average floor routine score of China's women's team.
INVESTOPEDIA EXPLAINS 'TTest'
The test statistic in the ttest is known as the tstatistic. The ttest looks at the tstatistic, tdistribution and degrees of freedom to determine a p value (probability) that can be used to determine whether the population means differ. The ttest is one of a number of hypothesis tests. To compare three or more variables, statisticians use an analysis of variance (ANOVA). If the sample size is large, they use a ztest. Other hypothesis tests include the chisquare test and ftest.
VIDEO

PTest
A statistical method used to test one or more hypotheses within ... 
Population
The entire pool from which a statistical sample is drawn. The ... 
Simple Random Sample
A subset of a statistical population in which each member of ... 
ZTest
A statistical test used to determine whether two population means ... 
Sample
A subset containing the characteristics of a larger population. ... 
Sample Selection Bias
A type of bias caused by choosing nonrandom data for statistical ...

How do you calculate the geometric mean to assess portfolio performance?
The geometric mean is used to calculate the central tendency of a set of numbers. It is the average of the logarithmic values ... Read Full Answer >> 
What is the difference between a simple random sample and a stratified random sample?
Simple random samples and stratified random samples differ in how the sample is drawn from the overall population of data. ... Read Full Answer >> 
What are the advantages and disadvantages of using systematic sampling?
As a statistical sampling method, systematic sampling is simpler and more straightforward than random sampling. It can also ... Read Full Answer >> 
What is the difference between the standard error of means and standard deviation?
The standard deviation, or SD, measures the amount of variability or dispersion for a subject set of data from the mean, ... Read Full Answer >> 
What level of correlation among investments will guarantee market returns but have ...
The efficient frontier set forth by modern portfolio theory (MPT) can provide an estimate of an optimal portfolio that allows ... Read Full Answer >> 
What is a "non linear" exposure in Value at Risk (VaR)?
The value at risk (VaR) is a statistical risk management technique that determines the amount of financial risk associated ... Read Full Answer >>

Investing
What's a TTest?
TTest is a term from statistics that allows for the comparison of two data populations and their means. The test is used to see if the two sets of data are significantly different from one another. ... 
Fundamental Analysis
Find The Right Fit With Probability Distributions
Discover a few of the most popular probability distributions and how to calculate them. 
Fundamental Analysis
What is Quantitative Analysis?
Quantitative analysis refers to the use of mathematical computations to analyze markets and investments. 
Fundamental Analysis
Understanding the Simple Random Sample
A simple random sample is a subset of a statistical population in which each member of the subset has an equal probability of being chosen. 
Economics
What is Systematic Sampling?
Systematic sampling is similar to random sampling, but it uses a pattern for the selection of the sample. 
Fundamental Analysis
Explaining Expected Return
The expected return is a tool used to determine whether or not an investment has a positive or negative average net outcome. 
Fundamental Analysis
Explaining the Geometric Mean
The average of a set of products, the calculation of which is commonly used to determine the performance results of an investment or portfolio. 
Investing
The Labor Market Recovery’s Missing Ingredient
Job creation is running at the fastest pace since the 90s, and there is some evidence that wage growth is finally starting to accelerate, albeit modestly. 
Trading Strategies
Best Undergraduate Degrees For Day Traders
We look at some popular undergrad majors for those wanting to begin a career in the exciting world of fastpaced trading. 
Fundamental Analysis
Explaining Standard Error
Standard error is a statistical term that measures the accuracy with which a sample represents a population.