Summer Vocab Flashcards
Statistics
Study of variability
population
group of interest, can be big or small
Variability
All things have differences, and statisticians look a these differences
2 branchs of AP stats
inferential and descriptive
descriptive stats
describe collected data using pictures or summaries like mean, median, range, etc…
inferential stats
look at data of sample and use it to tell about the population
compare descriptive and inferential stats
descriptive explains about data; inferential uses data of sample to tell about an entire population
data
any collected info., generally each little measurement
sample
A subset of population, taken to make inferences about the population, calculate statistics from samples
compare population to sample
populations generally are large, samples are small subsets of population; take samples to make inferences about populations, use statistics to estimate parameters
compare data to statistics
data is the individual bits of info collected, summarize data by, ex. finding mean of a group of data,
mean of sample is statistic, if data is from each member of population, mean is parameter
compare data to parameters
data is the individual bits of collected info, summarize data by, ex. finding mean of a group of data,
mean of sample is statistic, summary of sample; if data is from each member of population, mean is parameter, summary of population
parameter
numerical summary of a population like mean, median, mode
statistic
numerical summary of a sample like mean, median, mode
Curious about average wait a Dunkin Donuts drive through: randomly sample cars and find the average wait time is 3.2 minutes. What is the population parameter, statistic, parameter of interest, data?
parameter is the true average wait time at that Dunkin Donuts, a number you don’t have and will never know. Statistic is 3.2 minutes, average of data collected. Parameter of interest= population parameter. Data is the wait time of each individual car, like “3.8 min, 2.2 min, 0.8 min.” Average of that data is statistic, and use that to make inference about the true parameter
Compare DATA-STATISTICPARAMETER using categorical
example
Data are individual measures… like meal preference: “taco, 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.”
Compare DATA-STATISTICPARAMETER using quantitative
example
Data are individual measures, like how long a person can hold their breath: “45
sec, 64 sec, 32 sec, 68 sec.” That is the raw data. Statistics and parameters are
summaries like “the average breath holding time in the sample was 52.4 seconds”
and a parameter would be “the average breath holding time in the population was
52.4 seconds”
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 ok for small populations (like Mr. Nystrom’s students) 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….
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, then the number 9 from that burger would be called
a datum, or a data value.
If I take a random sample 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, then 9.5 is considered a
statistic. (t is a summary of a sample.)
If I take a random sample of 20 hamburgers from FIVE GUYS and count the number of pickles on a bunch of them… and I do this because I want to know the true average number of pickles on a burger at FIVE GUYS, the true average number of pickles is considered a
parameter, a one number summary of the population. The truth. AKA the
parameter of interest.