Introduction to Statistics Flashcards
Practice and study of collecting and analyzing data
Statistics
Two main branches of statistics:
Descriptive/summary
Inferential
Descriptive statistics is what?
Describing or summarizing our data
Inferential statistics is what?
Collect a sample of data, and apply the results to the population that the sample represents
Limitation of statistics
Statistics require specific measurable questions
Types of data:
Numeric/quantitative data
Categorical/qualitative data
What is continuous data?
Data measured on a continuous scale
What is interval/count data?
Data that are measured in whole numbers
Common way of visualizing the relationship between numeric data
Scatter plot
What is nominal data?
Data that describes unordered categories
What is ordinal data?
Categories of data are in order
Best way to visualize categorical data?
Group the values and perform aggregation
What is a histogram?
Takes data points and separates them into bins or ranges of values.
Where is the center of the data?
Mean
Median
Mode
Measures of center: mean is often called
Average
How to calculate the mean?
adding up all the values and divide by the number of values
Measures of center: median is what?
Middle value for a given variable
Measures of center: mode is what?
Most frequent value
When data is not symmetrical what measure of center should we use?
Median
What is spread?
describes how far apart data points are.
Why is spread important?
Tells us how much variety may occur in our data
Different measures of spread?
Range
Variance
Quartiles
What is range?
Difference between the max and min values
What is variance?
Calculates the average distance from each data point to the mean
How to calculate for the variance?
Measure the distance (value - mean) from each data point to the mean value
then squared
Standard Deviation
square root of the variance
Standard deviation close to zero, the more closely clustered the data is around the mean.
true
What are quartiles?
Splitting the data into four equal parts
Second quartile is the middle value = to the median
true
We can visualize quartiles using what?
A Box plot
The left edge of the box in the box plot represents the what?
First quartile
The middle line of the box in the box plot represents the what?
Median
The right edge of the box in the box plot represents the what?
the third quartile
Extreme values are shown
Beyond the horizontal lines
Interquartile Range (IQR)
Distance between the first and third quartiles
Benefits of IQR
Less affected by extreme values
