Statistics Flashcards
Statistics
The Study of Variability
Variability
How things differ
Ex. Eye Color, Race, Behavioral
Branches of AP STATS
Inferential and Descriptive
Descriptive Stats
Descriptions of the collected data
Inferential Stats
When you take data from a sample and use it to make a inference about a population
Difference between Descriptive and Inferential Stats
Descriptive Stats describes sets of data. Inferential Stats draw conclusions on data based on sampling
Data
Any collected info, each little measurement
Population
The group of interest. Can be big (US population) or small (High School Class)
Sample
A subset of the population. Often taken to make inferences about population. Used to calculate statistics
Comparing Population and Samples
Population contains all members of the specified group. Samples contain part (sample) of the population. Sample size are always smaller than population size.
Compare Data to Statistics
Data is any collected data, each little measurement. Statistics is the numerical summary of the sample of data.
Compare Data to Parameters
Data is the info we collect from the subjects. We the summarize and find the average. If it is a sample, you can call the average found a statistic.
If we have data from each member of the population, the average is called the parameter
Parameter
A numerical summary of a population. Mean, Median
Mode ect of population.
Statistic
A numerical summary of a sample. Mean, Median,
Mode, ect of a sample.
You wanted to find the average wait time at a Dunkin drive through in your neighborhood. You randomly sampled cars and found 3.2 minute average wait time. What is population parameter? What is the statistic? What is the parameter of interest? What is the data?
Population Parameter: True average wait time at that Dunkin.
Statistic: 3.2 minutes. Average of the data collected
Parameter of Interest: True average wait time of all cars
Data: Wait time of each individual car. Data taken by each car used to find average, which is called a statistic. You then make an inference of the true parameter
Compare Data/ Statistic/ Parameter using categorical example
Data: Individual measures like meal preference/ hair color ect.
Statistic/Parameter: Summaries. Statistic would be 42% of
SAMPLE preferred tacos
Parameter would be 42% of POPULATION preferred tacos.
Compare Data/ Statistic/ Parameter using quantitative example
Data: Individual measures like how long can a person be underwater. 10 sec, 15 sec, 20 sec is raw data.
Statistic: Summary of data. Average time underwater in the SAMPLE was 10.3 seconds
Parameter: Summary of data. Average time underwater in the POPULATION was 10.3 seconds
Census
When information is gathered from every member of the population
Does a Census make sense?
It is ok for small populations (surveying a high school class) but impossible if you wanted to survey all US teens
Difference between a Parameter and a Statistic
Parameters come from populations while Statistics come from samples
Random sample from 20 burgers at FG and counted the pickles on them and one of the burgers has 9 pickles, the 9 from that burger is the___
Datum or data value
Random sample from 20 burgers at FG and counted the pickles on them and the average number of pickles was 9.5, then 9.5 is considered a ____
Statistic
Random sample from 20 burgers at FG and counted the pickles on them and I do this to find the true average number of pickles at FG, the true average number of pickles is considered a ____
Parameter