Section 1.1 Getting Started Copyright © 2008 by Hawkes Learning Systems/Quant Systems, Inc. All rights reserved. HAWKES LEARNING SYSTEMS math courseware specialists Section 1.1 Getting Started

Statistics is the numerical description of sample data. HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Definitions: Statistics is the science of gathering, describing, and analyzing data. Statistics is the numerical description of sample data.

Data – information, in particular, information prepared for a study. HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Definitions: Data – information, in particular, information prepared for a study. Population – a particular group of interest. Parameter – a numerical description of a particular population characteristic. Census – when data is collected from every member of the population.

Sample – a subset of the population from which data is collected. HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Definitions: Sample – a subset of the population from which data is collected. Sample Statistic – a numerical description of a particular sample characteristic.

Group I want to know about Group I do know about HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Population Sample Whole group Part of the group Group I want to know about Group I do know about Characteristics are called parameters Characteristics are called statistics Parameters are generally unknown Statistics are always known Parameter is fixed Statistics change with the sample

Population = all college students Sample = 359 college students HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Identify the population and the sample. In a survey, 359 college students were asked if they had tried Vanilla Coke. 83 said yes. Population = all college students Sample = 359 college students A survey of 1125 households in the U.S. found that 65% subscribe to digital cable. Population = all U.S. households Sample = 1125 households

HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Is the numerical value a parameter or a statistic? The average grade on Test 1 in Ms. Shirley’s statistics class is an 87. Parameter The average Math score for all high school graduates on the SAT was a 519. In a survey of 135 college students, 52% of them said they plan to attend graduate school. Statistic

Identify the population and sample. HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started The principal of a large K-12 school is considering adopting a dress code for the upcoming school year. Before going to the school board, he wants to know the percentage of parents who would favor a dress code. He randomly chooses 15 families from each grade to interview. Out of the 195 families surveyed, 76% favor a dress code. Identify the population and sample. Population = all families of the students at the school Sample = 195 families Does the value “76%” represent a parameter or a statistic? Statistic

HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Branches of Statistics: Descriptive statistics – gathers, sorts, summarizes and displays the data; “just the facts”. Inferential statistics – uses descriptive statistics to estimate population parameters; an educated guess about the population based on the facts.

HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started Identify the descriptive statistic(s). What inferences can be made? In a survey of 100 students, 83.2% of students are happy with the food in the cafeteria. Descriptive statistic: 83.2% of the 100 students surveyed are happy with the food in the cafeteria. Possible inferences: 83.2% of all students are happy with the food in the cafeteria.

HAWKES LEARNING SYSTEMS math courseware specialists Introduction to Statistics 1.1 Getting Started