Chapter 1/4

Descriptive Statistics

summarizes and organizes data

Descriptive Statistics: Example

Mean, Median, Mode, SD, Variance

Inferential Statistics

Makes predictions or inferences about a population based on a sample

Nominal Data

categories with no inherent order

Nominal Data: example

hair color, gender

Ordinal Data

Ranked categories without values

Interval Data

Numeric values with equal intervals between values

Ordinal Data: example

Customer satisfaction(poor-excellent)

Interval Data: Example

Height, IQ score, Temperature

Parameter vs Statistic

A descriptive measure of the population is a parameter, a measure of the sample is the statistic

What are the measures of Central Tendancies?

Mean, Mode, Median

What are the measures of variability?

Range, Variance, SD, CV

Empirical Rule (per 1-3 K)

68%, 95%, 99%

What are the measures of Relative Standing?

Percentiles, Quartiles, and Interquartile range

Percentile

The percent of a distribution that is equal to or below it

Right Skew

The tail is to the right. The mean is greater than the median

Left Skew

The tail is to the left. The mean is less than the median