Week 8 Flashcards
Concepts of statistics
Define statistics
a science that studies the collection, analysis, interpretation, presentation and organisation of data
The population is
the total set of observations of a group we study (N)
A sample is
a set of observations taken from the total population (n)
Variables are
things we measure, control or manipulate
Measures of central tendency (location)
mean, mode and median
Measure of spread (dispersion)
Range, quartiles, variance and standard deviation
Is the variance an unbiased estimator of the population?
No, the sample range tends to underestimate the population range
Standard deviation is
the square root of the population variance
Define probability density function
a function that describes the relative likelihood for a random variable to taken on a given value
TRUE OR FALSE
- The PDF is non-positive everywhere?
- The integral over the entire space is equal to 0?
- False, it is non-negative everywhere
2. False, it is equal to 1
What is a uniform distribution?
A family of symmetric probability distributions. Can be continuous or discrete data
Which 2 parameters are normal distribution defined by?
Location (mean) and scale (variance)
What are the parameters of a standard normal distribution?
Mean = 0 Variance = 1
Define accuracy, precision and bias
Acc - how close measurements are to the true value trying to be measured.
Prec - how repeatable the measurement is within itself
Bias - a systematic lack of accuracy in which all data deviates from true value in same direction
What is the purpose of a statistical test?
To evaluate the relationship between variables
