Mean, Standard Deviation, Z score, Sampling Definitions, Population and Samples Descriptive vs. Inferential Statistics Apply definition in statistics

1. Mastering Statistics
Mean, Std Deviation, Variance, Z-score, Sampling

2. Lesson 2 – Populations and Samples - definitions
 Statistics: Gathering, describing & analysing data. OR numeric description of sample data
 Data: Information Gathering
 Population: Particular group of interest ex: everybody in a city; everybody in something,
 ex: all males or all females, all children between 6-9 ya, ex: everybody in a city; .
 Note the word ALL, is all inclusive of a category
 Parameter: Numerical description of a population characteristic
 Ex: the mean height of all males in the world; IQ of all children in the world, mean IQ of all females in USA, 75% of all kids age
6-9 play games
 Note the word NUMERICAL from definition; it is a number
 Sample: Subset of the POPULATION from which DATA is collected
 Ex: we asked 100 males IN THE CITY what their fav movies
 Sample Statistic: Numeric description of particular sample CHARACHTERISTIC
 Ex: 100 female asked from city; 47% disliked chocolate

3. Lesson 3 – Descriptive vs Inferential Statistics
Branches of statistics
 Descriptive Statistic – gather, sort, summarise data from sample
 Inferential statistics – use descriptive statistics (DATA) to ESTIMATE POPULATION PARAMETERS
 Problem: Based on a phone survey, 22% of all men dislike football
 Inferential as we estimate the percentage of a population from a sample (survey)
 PR2: 65% of seniors at a local HS apply to college plan to major in business
 Descriptive because
Population
Sample

4. Lesson 4 – Apply Definitions in Statistics
 Height of every 4th bottle on an assembly line: Sample
 Ages of all USA president: Population
 A research stop 100 people in a store to ask a survey of household income
 Population: people in a store
 Sample: 100 people chosen
Parameters describe populations, statistics describe sample
 The average number of hour per week a sample of 10 yo. spend watching TV is 20h
 Statistic: 20h/week for the sample
 87% of all patients in a hospital report having alcohol problem.
 Parameter: describe all patients