Descriptive vs inferential statistics
Descriptive statistics used to describe your sample population, Summary statistics, data analysis begins with descriptive statistics. Methods of organizing, summarizing, and presenting data in an informative way.
Inferential statistics
The methods used to estimate a property of a population on the basis of a sample.
Type of variables are Qualitative vs Quantitative data
Quantitative - numerical, example: age. Qualitative - Non-numerical, example: favorite color.
Quantitative sub set:
Discrete involves whole numbers, example: # children. Continuous can be decimal or fraction, example gallons of gas.
Four level of measurements
1) Nominal level: Qualitative - no order, example: favorite color. 2) Ordinal level: - likerscale, is order. 3) Interval: Quantitative - doesn't have a meaningful zero and ratios doesn't make sense, Example like temperature, or dresses sizes. 4) Ratio lev
Examples:
Examples are from quiz one:
What type of variable is "projected return on an investment"?
Continuous it can be decimal or fraction, example gallons of gas.
What type of variable is the number of robberies reported in your city?
Discrete because it involves whole numbers, example: # children. Continuous can be decimal or fraction, example gallons of gas.
The change in daily price of stock is what type of variable?
Quantitative is numerical, example: age.
A questionnaire contained a question regarding marital status. The respondent checked single, married, divorced, separated or widow. What is the scale of measurement for this question?
Nominal - Is Qualitative - no order, example: favorite color.
What type of variable is the number of gallons of gasoline pumped by a filling station during a day?
Quantitative is numerical, example: age.
Using a sample to make generalization about an aspect of a population is called
Statistical inference.
The Nielsen Ratings break down the number of people watching a particular television show by age. Age is what level of measurement?
Ratio, Ratio level: - income, # of cars, # of children, Ratio makes sense and has a meaningful zero.
A bank ask customers to evaluate the drive-thru service as good, average, or poor. Which level of measurement is this classification?
Ordinal - likerscale, is order.
What type of variable is student ID number?
Qualitative is Non-numerical, example: favorite color.
The main purpose of descriptive statistics is to:
Summarize data in a useful and informative manner.
What is a portion or part of a population called?
Sample
Dr. Lewis asked her students their ages. On the basis of this information, she states that the average age of all the students at Troy University Phenix City is 34 years. This is an example of
Inferential statistics
A _______ variable can have values that are number on the real number line.
Quantitative
Which word is NOT part of the definition of descriptive statistics?
Predicting
A consume's yes/no reply to a survey question is what type of variable?
Qualitative