DEFINITION of 'T Distribution'
A type of probability distribution that is theoretical and resembles a normal distribution. A T distribution differs from the normal distribution by its degrees of freedom. The higher the degrees of freedom, the closer that distribution will resemble a standard normal distribution with a mean of 0, and a standard deviation of 1.
The T distribution is also known as the "Student's T Distribution".
BREAKING DOWN 'T Distribution'
The use of a T distribution is precluded by the standard deviation of the population parameter being unknown and allows the analyst to approximate probabilities, based on the mean of the sample, the population, the standard deviation of the sample and the sample's degrees of freedom. As the sample's degrees of freedom approaches 50, the T distribution will virtually be identical to the normal distribution.

Probability Distribution
A statistical function that describes all the possible values ... 
Normal Distribution
A probability distribution that plots all of its values in a ... 
Sampling Distribution
A probability distribution of a statistic obtained through a ... 
Bell Curve
The most common type of distribution for a variable. The term ... 
Uniform Distribution
In statistics, a type of probability distribution in which all ... 
Distribution
1. When trading volume is higher than that of the previous day ...

Investing
What a Normal Distribution Means
Normal distribution describes a symmetrical data distribution, where most of the results lie near the mean. 
Investing
Find The Right Fit With Probability Distributions
Discover a few of the most popular probability distributions and how to calculate them. 
Investing
Using Normal Distribution Formula To Optimize Your Portfolio
Normal or bell curve distribution can be used in portfolio theory to help portfolio managers maximize return and minimize risk. 
Trading
Trading With Gaussian Models Of Statistics
The entire study of statistics originated from Gauss and allowed us to understand markets, prices and probabilities, among other applications. 
Investing
Stock Market Risk: Wagging The Tails
The bell curve is an excellent way to evaluate stock market risk over the long term. 
Investing
The Uses And Limits Of Volatility
Check out how the assumptions of theoretical risk models compare to actual market performance. 
Investing
Explaining Standard Error
Standard error is a statistical term that measures the accuracy with which a sample represents a population. 
Financial Advisor
Stretch Your Savings By Working Into Your 70s
Staying employed a little longer may allow for a more comfortable retirement. 
Financial Advisor
How to Navigate Taxable Mutual Fund Distributions
It's almost time for yearend capital gains distributions for mutual funds. Here's how to monitor them and minimize their tax impact. 
Investing
Explaining the Empirical Rule
The empirical rule provides a quick estimate of the spread of data in a normal statistical distribution.

Is my nonqualified Roth IRA distribution subject to taxes or early distribution ...
The ordering rules must be applied to determine whether the distribution is subject to income taxes and/or the early distribution ... Read Answer >> 
What are the exceptions to the early distribution penalty for a nonqualified Roth ...
The exceptions are as follows: The distribution is made on or after the date you reach age 59.5 The distribution is made ... Read Answer >>