EIP - Normal Distribution - Week 6 Flashcards
Are normal distributions symmetrical?
Yes
What can a normal distribution be completely described by (2) and why?
By its mean - a measure of central tendency
By its standard deviation - a measure of its variability
What is the central limit theorem?
If random samples are taken from any distribution, then the distribution of sample means will be normal
What happens when a small sample of the population is taken? What would repeated small sample distributions look like? How does a t-distribution fit in?
The sample distribution will not look normal
Repeated small sample distributions may not look like each other
The t-distribution allows you to see whether the difference between repeated small samples is real or due to random variation
What happens to uncertainty in t-distributions the smaller the number of data points? what happens to the tails of the distribution?
The smaller the number of data points, the greater the uncertainty and the bigger the tails
What happens to the tails of a distribution with smaller degrees of freedom?
They become wider