The Terminology of Statistics STT 2810 August 24, 2011 Mr. Caleb Marsh

Fundamentals Data – observations (measurements, genders, survey responses, etc.) that have been collected. Statistics (the science of) – a collection of methods for planning studies and experiments, obtaining data and then organizing, summarizing, presenting, analyzing, interpreting and drawing conclusions based on data.

Where do we get our data from? Population – the complete collection of all elements (scores, people, measurements, etc.) to be studied. The collection is complete in the sense that it includes all subjects to be studied.

How do we get our data? Census – the collection of data from every member of the population. Sampling – a sub collection of members selected from the population. www.census.gov

What is all this data trying to describe? Parameter – a numerical measurement describing some characteristic of a population. Statistic – a numerical measurement describing some characteristic of a sample. Ex – 95% of all ASU students possess a driver’s license Parameter Ex – A sample of 1087 voters showed that 10% are still undecided about how they will vote in the upcoming primaries. Statistic

Types of Data Qualitative Data – Can be separated into different categories that are distinguished by some non-numeric characteristic. Also called categorical data. Examples – Gender, Political Party Preference, Hair / Eye Color Generally thought of as “word” responses.

Types of Data Quantitative Data – Consists of numbers representing counts or measurements. Height, Weight, IQ scores

Quantitative Data Discrete Data – Occurs when the number of possible values is a finite (countable) number. Continuous Data – Results from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions or jumps.

Quantitative Data Ex – The number of students registered for a class at a university. Discrete Ex – The ages of the students in that classroom. Ex – The amount of gasoline used in a month. Continuous Ex – Miles driven by a motorist in a given day. Ex – The number of cars currently owned in the US .