Summer Work Flashcards
What is Statistics?
the study of variability
what is variability?
differences… how this differ. there is variability everywhere. we all look different, act different, have different preferences… statisticians look at these differences.
what are 2 branches of ap 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 it 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)
compare descriptive and inferential stats
descriptive explains about the data that you have, inference uses that data you have to try to say something about the entire population
what is data?
any collected information. generally each little measurement… like if it a survey about liking porridge… the data might be “yes, yes, no, 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 are interested in. sometimes it’s big like “all teenagers in the US” other times it’s 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 that mean a “statistic” if we have data from each member of a population, then that mean is called a “parameter”
compare data to parameters
(2)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 that mean a “statistic” if we have data from each member of a population, then that mean is called a “parameter”
what is a parameter
a numerical summary of a population. like a mean, median, rage… of a population
what is a statistic?
a numerical summary of a sample. Like mean, median, range… of a sample
We are curious about the average wait time at a Dunkin’ donuts drive-thru 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 of interest is 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 min, 2.2 min, .8 min, 3 min.” you take that data and fine 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 categorical example
data are individual measures… like meal preference: “taco, taco, pasta, taco, 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
compare data-statistic-parameter using quantitative example
data are individual measurements, like how long a person can hold their breath “45 sec, 64 sec, 32 sec, 68 sec.” this is the raw data. statistics and parameters are summaries like “the average breath holding time in the sample was 52.4 sec” and a parameter would be “the average breath holding time in the population was 52.4 sec”
what is a census?
like a sample of the entire population, you get information from every member of the population
does a census make sense?
a census is okay for small populations but impossible if you want to survey all US teens
what is the difference between a parameter and a statistic?
BOTH ARE A SINGLE NUMBER SUMMARIZING A LARGER GROUP OF NUMBERS… but PPPARAMETERS come from PPPOPULATIONS… SSSTATISTICS come from SSSAMPLES
if i take a random sample of 20 hamburgers from five guys and count the number of pickles on a bunch of them and one of them had 9 pickles, the number 9 would be called a what?
a datum or data value
if i take a random sample of 20 hamburgers from five guys and count the number of pickles on a bunch of them and the average number of pickles was 9.5, 9.5 is considered a what?
a statistic