Lesson 1: Intro to Statistics

Question 1

What are statistics?

Answer 1

Set of mathematical procedures for organizing, summarizing, and interpreting information

Question 2

What is a population?

Answer 2

The entire group of individuals
- ex: PSYC204 students

Question 3

What is a sample?

Answer 3

A smaller group selected from the population
- ex: students that participate to the polling in class

Question 4

What is a variable?

Answer 4

A characteristic or condition that can change or take on different values

Question 5

What is data?

Answer 5

The measurements obtained in a research study
- ex: answers during the first polling in class (excited, nervous, hungry, etc.)

Question 6

What are descriptive statistics?

Answer 6

Methods for organizing and summarizing data
- ex: tables, graphs, averages

Question 7

What is a descriptive value for a population? For a sample?

Answer 7

Population: parameter
Sample: statistic

Question 8

What are inferential statistics?

Answer 8

Methods for using sample data to make general conclusions (inferences) about populations
- “margin of error,” “statistically significant”

Question 9

What is sampling error?

Answer 9

Discrepancy between a sample statistic and its population parameter
- you want to minimize the sampling error, but it’s hard to, since you can’t ever get the whole population parameter (you only get statistics, which are from samples)

Question 10

What are the two main types of variables?

Answer 10

1. Discrete variables: consist of indivisible categories, each unit being the smallest it can be
   - fruit, political party, etc.
2. Continuous variables: infinitely divisible into whatever units a researcher may choose
   - ex: time, weight, height, etc.

Question 11

What are real limits?

Answer 11

Boundaries of each interval representing scores measured on a continuous number line
- upper real limit marks the top of the interval
- lower real limit marks the bottom of the interval

Question 12

What is a nominal scale?

Answer 12

An unordered set of categories identified only by name
- ex: fruit categories

Question 13

What is an ordinal scale?

Answer 13

An ordered set of categories. Can tell you the direction of difference between two individuals
- ex: small, medium, large

Question 14

What is an interval scale?

Answer 14

An ordered series of equal-sized categories. Can identify the direction and magnitude of a difference.
- zero value does NOT mean none of the quantity
- ex: temperature

Question 15

What is a ratio scale?

Answer 15

Interval scale where a value of zero indicates NONE of the variable. Can identify the direction and magnitude of differences and allow ratio comparisons of measurements
- ex: time, weight, height, etc.

Question 16

What is an experiment?

Answer 16

One variable is manipulated to create treatment conditions. A second variable is observed and measured to obtain scores for a group of individuals in each of the treatment conditions
- demonstrates cause and effect relationships

Question 17

What is the independent variable? The dependent variable?

Answer 17

Independent variable is the manipulated variable. Dependent variable is the observed variable

Question 18

What is the best way to study the effectiveness of a treatment?

Answer 18

Randomized control trial
- two instances are observed and then compared to determine the effectiveness of each treatment

Question 19

What are non-experimental or quasi-experimental studies?

Answer 19

These studies to NOT use a manipulated variable to differentiate the groups
- the variable that DOES differentiate the groups is usually a pre-existing participant variable, like male/female or before/after