stat tutor section 2 notes - CONCEPT SHEET FOR DESCRIPTIVE...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
CONCEPT SHEET FOR DESCRIPTIVE STATISTICS TUTORIAL Sampling Sampling is the random selection of a subset of objects/events from a larger population. Inferences to the population are based on conclusions made about the sample. Data are records made from a sample of objects/events. Individual data are called replicates . Descriptive statistics includes methods for transforming data in order to better understand it. A bell-shaped or normal data distribution usually results when a random sample is drawn from a larger population. Normal Curve The mean , median , and mode are descriptive parameters that characterize a sample’s central value. The mean ( X ) is the sum of all data values ( x i ) divided by the sample size n or × = Σ× i / n The median is the middle data value at position (n + 1)/2 when the data are ordered. The range , variance and standard deviation are descriptive parameters that characterize a sample’s variability. The range is the smallest data value subtracted from the largest value.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/04/2008 for the course BIO G 1103 taught by Professor Ransler during the Fall '07 term at Cornell University (Engineering School).

Ask a homework question - tutors are online