Descriptive / Inferential Statistics In Descriptive Statistics we summarize or describe the process which yields the data we are analysing. The set of all potential data is referred to as a population. # 35% of the students in this class have Casio watches. # The average age of a Ryerson student is 23.4 years. In Inferential Statistics we attempt to infer something about a population (or the process which generates it) from a sample (population subset). # Infer the concentration of white blood cells in a sick patient. # Estimate the Life Expectancy of Sony CD player for the purpose of setting a guarantee..
Descriptive / Inferential Statistics Population Parameters: Any characteristic of a population. Not all populations can be characterized by the same set of parameters. Parameters are fixed! # Mean age of a 1st semester Business Student is 19.12 years. [17,18,20...] # Proportion of males in the Business Building is 47.2% [M, F, F, M, M ..]
Descriptive / Inferential Statistics Sample Statistic: A value calculated from a sample to be used to infer an understanding of a population. # (Sample) Mean age of a student in this classroom which will be used to estimate the (population) mean age of a mean age of a 1st semester Business Student is 20.3 years. # (Sample) proportion of males in this classroom which will be used to estimate the (Proportion) of males in the Business Building is 53% # Concentration of white blood cell from a sample to diagnose a patient. # Mean life expectancy of a sample of Sony CD players for the purpose of setting a guarantee.
Descriptive / Inferential Statistics