Statistics: Descriptive vs. Inferential, Variables and Data Types - Prof. Robert Herbert, Study notes of Business Statistics

Download Statistics: Descriptive vs. Inferential, Variables and Data Types - Prof. Robert Herbert and more Study notes Business Statistics in PDF only on Docsity! Descriptive statistic vs. inferential statistics Descriptive- example (class average)(max score on test or min.) summarizes Population-collection of all objects being studied Sample- (roughly) as subset of the population Inferential- to try and make inferences about an entire population based on information obtained in a sample. Variable- characteristic of each element of a population Example: population=LSU students Variables might be… gender, age, weight…etc. Perimeter- a numerical characteristic of an entire population Example: LSU population… perimeter might be average age Statistic- a numerical characteristic of a sample Data- the information obtained from a sample CHAPTER TWO Variables Categorical variables- non numerical (example: letter grade on a test, gender, major) Numerical variables- age, weight, time Continuous – a numerical random variable is continuous if the possible values that the variable takes are an entire interval of real numbers (age, weight, time at LSU) Discrete- a numerical random variable is discrete if between any two values that the rv could assume, there is an interval of numbers that the random variable cannot assume. (Any RV, which counts the number of occurrences of some phenomenon) *If a numerical rv may only assume a finite number of values then it must be discrete. Levels of data: Nominal data: no natural order or ranking to the data (asking favorite ice cream- no flavor is better than the other/opinion) Ordinal data: a natural order or ranking to the data (numerical grade or letter grade) you don’t know how much more something is worth. Interval class data: there is a natural order to the data and also one can meaningfully measure how much more one element is compared to another. There is no natural 0. (Temperature)