Stats 1124: CH 1
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What is data?
Data are "numbers" with a context. (A set of measurements)
What is an individual?
An Individual is an object that is being described by the data.
What is a variable?
A variable is any characteristic of an individual and can take different values for different individuals.
What is a special variable? (Ex. People's names)
What are the two types of data?
A sample or a population
What are the two types of variables?
Why are quantitative variables better than categorical variables?
Because, Quantitative variables can be converted to categorical variables but categorical variables CANNOT be turned to quantitative variables.
What two graphs are used for categorical data?
Bar graphs and Pie Charts
What two graphs are used for Quantitative Data?
Stemplots and Histograms
"How Often" a variable takes place can be measured in what three ways?
2. Relative frequency (proportion) = Frequency/Total
3. Percentage = 100 x Relative frequency
A stemplot organizes data into groups called ____
What are the values within each group of stemplot called?
What is a disadvantage of using a stemplot?
It can only be useful for small datasets
What do the height of bargraphs show?
It shows "How often" measurements fall in a particular class
whats the differences between a histogram and bar graph?
There is a space inbetween for bar graphs
What does Bimodal mean?
When the graph has two local peaks
What does it mean by "variables are NOT fixed numbers"?
This mean's that they could have many different values to them.
For example: "Brown hair colour" is a fixed data but "People's hair colour" is a variable.
For example: "120 pounds" is just data but "People's weight" is as variable
What is relative frequency?
Relative frequency = frequency ÷ number of observations
What is percentage frequency?
Percentage frequency = relative frequency X 100 = f ÷ n X 100
What are four differences between bar and pie charts?
1. Pie charts must include ALL categories
2. Bar charts canuse more than 2 groups
3. Bar charts are more accurate
4. Pie charts are only good for one group or must draw two pie charts
What is a parento chart?
When the bar graph is going by smallest to largest order by height(small to large)
Stats 1124: CH 1
Chapter 1 Picturing Distributions with Graphs