Chpt 2 - Organizing and Graphing Data Flashcards
Why do we need to learn how to organize data?
Without organizing the raw data, we cannot obtain useful information
What is data that is non-numerical, such as gender called?
Categorical
Also called qualitative
What is data that is numerical, such as the ages of the people involved in the study?
Numerical
Also called quantitative
What is a variable?
A variable is a characteristic that varies from one person or thing to another.
Examples include gender, age, marriage status, number of email accounts, monthly salary, height, weight, etc.
Basically all of the headings of the columns is considered a variable
What is the formal definition of data?
The values of a variable in a sample.
How can we categorize variables? How can these be further broken down?
Categorical (qualitative) or Numerical (quantitative)
Numerical variables can be further broken down to:
Discrete or continuous
Categorical variables can be further broken down to:
Nominal or ordinal
What are the types of numerical variables?
Discrete or continuous
What is a discrete variable? Give some examples
A numerical variable whose values can be listed
An example might be how many email addresses do you have? If you say 4, the person would be able to list out their 4 email addresses.
What is a continuous variable? Give some examples
A numerical variable whose possible values from some interval of numbers
Height is a continuous variable because its possible value is any number from 40cm to 300cm. While the height may not change once we are adults, we often don’t measure it in just feet….we use feet and inches, making this continuous as a value
Other examples are weight, temperature, and length.
Is age a discrete or continuous variable?
Age is also considered discrete because while you are constantly aging, we only list out age as whole numbers.
Anytime we are counting such as 1, 2, 3, it is considered discrete
That being said, with babies, we do measure the partial intervals, such as 1.5 years, or kids are only 5 days away from their next birthday…this context with looking forward and using increments, its considered a continuous variable
What is a non-numerical variable that has no specified order called?
Give an example
Nominal
Marital status…there is no actual order in life that is set, you may get married, be common law, get separated, be single etc. without a defined order that everyone follows
What is a non-numerical variable that has an order called?
Give an example
Ordinal
In many studies, there may be very like, like, neutral, dislike, or very dislike
If in a study, they coded females as 1 and males as 2, does this make it a numerical variable?
How can you test if the value is numerical or non-numerical?
No, it’s still a categorial variable because the numbers are meaningless and have no mathematical meaning
To check, do some basic math operations, if it makes sense it’s a numerical variable, if not, it is a non-numerical value. For example, if females are 1 and males are 2, you cannot add two females together to make 1 male. haha
What is the purpose of organizing data?
To analyze the distribution of a variable
What methods can we use to organize categorical data?
Numerical methods (frequency and relative frequency tables)
Graphical methods (pie charts and bar charts that help visualize the frequency/relative frequency tables)