Data
A study is done in which the data collected are the number of cars a person has owned in his or her lifetime. This is an example of qualitative data. (T/F)
False - Data is quantitative
Sampling Distributions
Distributions of sample statistics such as means and proportions
What are the names given to values that describe samples (1) and values that describe populations (2)?
1. Statistics 2. Parameters
Random Variable
A numerical outcome of an experiement or random phenomenon
What is a random variable?
A numerical outcome of an experiment or random phenomenon
Survey
A random study, generally in the form of an interview or questionnaire, that provides researchers with information about a certain population
Probability Distributions
A way of matching outcomes with their probabilities of success
Which of the following are examples of qualitative data? (A) The airline on which a person chooses to book a flight (B) The average number of women in chapters of Gamma Goo sorority (C) The race/ethnicity of survey respondents (D) The closing Dow Jones average on 50 consecutive market days (E) The number of people earning each possible grade on a statistics test (F) The scores on a given exam
A, C, E, F (if letter grades were given)
Descriptive Statistics (Exploratory Data Analysis)
Analytic or graphic data
Continuous Data
Can be measured or take on values in an interval (quantitative) - ex. time of day
Qualitative Data (Categorical Data)
Data that can be classified into a group
Discrete Data
Data that can be listed or placed in order (quantitative) - ex. number of heads in 20 coin flips
Quantitative Data
Data that can be measured or identified on a numerical scale
Which of the following are discrete and which are continuous? (A) The number of jelly beans in a jar (B) The ages of a group of students (C) The humidity in Atlanta (D) The number of ways to select a committee of three from a group of ten (E) The number of people who watched the Super Bowl in 2002 (F) The lengths of fish caught on a sport fishing trip
Discrete: A, D, E Continuous: B, C, F
Control Group
Group that receives no stimuli in an experiment
Treatment Group
Group that receives the stimuli in an experiment
Why do we need to take care with data collection?
In order to avoid bias
Why do we need to sample?
It is usually too difficult or too expensive to survey every member of the population
Which of the following are statistics an which are parameters? (A) The proportion of all voters who will vote Democrat in the next election (B) The proportion of voters in a Gallup Poll who say they will vote Democrat in the next election (C) The mean score of the home team in all NFL games in 2005 (D) The proportion of Asian students among all students attending high school in the state of California (E) The mean difference score between a randomly selected class taught statistics by a new method and another class taught by an old method (F) The speed of a car
Statistics: B, E, F Parameters: A, C, D
A study is done in which the data collected are the number of cars a person has owned in his or her lifetime. This is an example of discrete data. (T/F)
True - Data is countable
Experiment Observational Study
Used to determine the reactions of persons or things to certain stimuli
Inferential Statistics
Using data from samples to make inferences about the population from which the sample was drawn
Parameters
Values that describe a population
Statistics
Values that describe a sample