What is Statistics? Lecture 1 Dave Brocker

What do you think of when you hear ‘statistics’?

Statistics

Statistics: The field of describing, analyzing, and making inferences based on data either from a sample or a population
Describing: What does the data ‘look’ like?
Analyzing: A mathematical approach to extracting information about the data
Inferences: Applying logical reasoning to predict what might happen in subsequent measurements. Typically, inferences are made from samples and extrapolated into what the population might be ‘expected’ to look like.
Data: Qualitative or Quantitative information that consists of measured or manipulated variables
Sample: A subset of the population of interest
Population: The entire set of interest.

Everywhere!

Statistics makes appearances anywhere you see information being summarized or being used to make decisions.

Everywhere!

Statistics makes appearances anywhere you see information being summarized or being used to make decisions.

Purchasing a car
- You look at reviews and infer the overall takeaway of how ‘good’ or ‘bad’ a car might be.
Going to a restaurant
- You base your selection on prior experiences or on reviews/opinions from people you trust
Voting for a candidate
- You look for increases in wages and decreases in taxes
- You look for promises of pollution reduction and energy increases
Going to the Movies
- You pick a movie based on genre, past experiences, and reviews

Statistical and data literacy is useful for being able to make informed decisions

If you were told that blueberries could cure Cancer, wouldn’t it be helpful to know how to evaluate that claim?

How many blueberries?
How long do you have to eat them for?
Is it all types of cancer or a specific one?
Is it truly that blueberries cure cancer or are they mixed in with something else?

Our brain is a pattern matching machine

We look for information that confirms our thoughts and surroundings
We would (often) prefer that things were nice and pretty, but reality is often not so simple

Mental Health Counselors/Social Workers
- Knowing that a certain percentage of college students suffer from Anxiety, you can improve your outreach and provide material aimed to address and reduce the impact
Human Resources/Training and Development
- If 30% of employees report that there are so few incentives and little to no sense of belonging, you can take actionable steps to address those issues

Researchers (Hey That’s What I do!)
- Hypotheses are only supported when the data suggests that the findings are unlikely to have occurred by chance.

Academia (Hey That’s What I do!)
- If the Average Exam score is an 85 with a Standard Deviation of 20 points, I have reason to believe that the test was either too difficult or the material was not explained well enough

Be comfortable looking at data and making inferences
Be comfortable looking at graphs and making inferences and gathering takeaways
Reading scientific and popular articles and critically thinking about the claims being made
Understand what constitutes evidence and what it means for hypotheses to be supported
Understand that research is probabilistic

Therapist:
- Your practices need to be informed by evidence-based treatments
Researcher:
- Your claims need to be supported by evidence that can assert a high probability or relationship or cause and effect.
Non-Data Field:
- Because data is everywhere, even in your Netflix recommendations!

Descriptive Statistics
- What does the data ‘look like’?
Probability is Paramount
- What are the chances this happens and what is the probability this only happens because of chance?
Testing hypotheses
- If [condition] has this specific attribute, we expect [event] to take place.
Correlation, regression, and causation
- How are variables related to each other?
- How much can variables predict each other?
- Does this variable cause a change in this other component?