Summer Work Flashcards
What is Statistics?
The study of variability.
What is variability?
Differences… how things differ. There is variability everywhere.. We all look different, act different, have different preferences.. Statisticians look at these differences.
What are the 2 branches of STATS
Inferential and Descriptive
What are descriptive STATS?
Tell me what you got! Describe to me the data that you collected, use pictures or summaries like mean, median, range, etc..
What are inferential STATS?
Look at your data and use that to say stuff about the BIG PICTURE…. like tasting soup… a little sample can tell you a lot about the big pot of soup (the population)
What is data?
Any collected information. Generally each little measurement. Like, if it is a survey about liking porridge… the data might be “yes, yes, yes, yes” if it is the number of saltines someone can eat in 30 seconds, the data might be “3,1,2,1,4,3,3,4”
What is a population?
The group you’re interested in. Sometimes it’s big, like “all teenagers in the US” other times it is small, like “all AP Stats students in my school”
What is a sample?
A subset of a population, often taken to make inferences about the population. We calculate statistics from samples.
Compare population to sample
Populations are generally large, and samples are small subsets of these populations. We take samples to make inferences about populations. We use statistics to estimate parameters.
Compare data to statistics
Data is each little bit of information collected from the subjects, they are the INDIVIDUAL little things we collect… We summarize them by, for example: finding the mean of a group of data. If it is a sample, then we call the mean a “statistic” if we have data from each member of population, then that mean is called a parameter.
Compare descriptive and inferential STATS
Descriptive explains the data you have, inferential uses that data you have to try to say something about the entire
population
Compare data to parameters
Data is each little bit of information collected from the subjects, the little things we collect.. parameters are the numbers that summarize an entire population
What is a parameter?
A numerical summary of a population. Like a mean, median, or range of a population.
What is a statistic?
A numerical summary of a sample. Like a mean, median, or range of a sample.
We are curious about the average wait time at a Dunkin Donuts drive through in your neighborhood. You randomly sample cars one afternoon and find the average wait time is 3.2 minutes. What is the population parameter? What is the statistic? What is the parameter of interest? What is the data?
The parameter is the true average wait time at that Dunkin Donuts. This is a number you don’t have and will never know. The statistic is “3.2 minutes.” It is the average of the data you collected. The parameter interest if the same thing as the population parameter. In this case, it is the true average wait time of all cars. The data is the wait time of each individual car, so that would be like “3.8 mins, 2.2 mins, .8 min, 3 min.” You take that data and find the average, that average is called a “statistic” and you use that to make an inference about the true parameter.
Compare DATA-STATISTIC-PARAMETER using a categorical example.
Data are individual measures… like meal preference: “tace, taco, pasta, taco, burger, burger, taco.”… Statistics and Parameters are summaries. A statistic would be “42% of sample preferred tacos” and a parameter would be “42% of population preferred tacos”