What is Statistics
it is the science of collecting, summarizing, presenting and analyzing data from the purpose of drawing conclusions and making decisions
the common used notations in statistics:
Population & Sample
- Population is a collection of all units of interest(may be people, households, geographic regions items produced ets).
- A sample is a subset of population from which the data is collected
Parameter
- A numerical characteristic of a population defined for a specific variable (Examples: Population mean, population proportion etc.)
Variables
- We are interested in one or more measurable properties or attributes associated with each unit in the population. These properties are called variables.
Population Parameters(or simply Parameters)
- summarize data for an entire population; Example: Population mean, Population proportion, population standard deviation
Sample Statistics (or simply Statistics)
- summarize data from a sample; Example: Sample mean, Sample proportion, Sample standard deviation
Estimate
- A sample statistic used to estimate an unknown population parameter
Sampling distribution
- which is the probability distribution of a sample statistic.
Random Experiment
- Procedure or an operation whose outcome is uncertain and cannot be predicted in advance.
Sample Space
- The collection of all possible outcomes of a random experiment events – Set of outcomes of a random experiment
probability distribution
- A probability distribution is a formula or a table used to assign probabilities to each possible value of a random variable X. A probability distribution may be either discrete or continuous. A discrete distribution means that X can assume one of a countable (usually finite) number of values, while a continuous distribution means that X can assume one of an infinite (uncountable) number of different values.