Summer Vocabulary Flashcards
What Is Statistics?
The study of variability
What is variability?
How things differ
What are 2 branches of AP STAT?
Inferential and Descriptive
What are DESCRIPTIVE stats?
describing data (mean, median, range…)
What are inferential stats?
using data to infer (using a sample to say something bout an entire population)
Compare DESCRIPTIVE and INFERENTIAL stats
descriptive talks about data you have, inferential uses data you have to make more general statements.
What is data?
any collected information
What is a population?
the group you are interested in
What is a sample?
a subset of a population
Compare population and sample
populations are generally large, and samples are parts of populations so are smaller. Samples are used to make inferences about populations. We use statistics to estimate parameters.
Compare data to statistics
Data is each bit of information collected from the subjects. They are Individual things we collect. We summarize these things with things like mean or mode which are “statistics”. Statistics from samples are called statistics and statistics from populations are called “parameters”.
Compare DATA-STATISTICS-PARAMETER using quantitative example
Data: individual measures of raw data
Statistics: summaries of data from a sample
Parameter: summaries of data from a population
What is a census?
like a sample of the entire population, you get information from every member of the population. Good for small populations but almost impossible for big ones like “all US teens”.
What is the difference between a parameter and a statistic?
both are a single number summarizing a larger group of numbers, however parameters=populations, statistics=samples.
What is a datum or a data value? REAL WORLD EXAMPLE
a single piece of data from a set of data (ex: random sample of 20 hamburgers from FIVE GUYS, and 1 of the burgers has 9 pickles, then the number 9 is a datum).
What is a statistic? REAL WORLD EXAMPLE
Random sample of 20 hamburgers from FIVE GUYS, the average number of pickles was 9.5, then 9.5 is a statistic.
What is a parameter? REAL WORLD EXAMPLE
If I take a random sample of 20 hamburgers from FIVE GUYS and count the numbers 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
What is the difference between a sample and a census?
Sample= info from a small part of the population (statistic)
Census=info from the entire population (parameter)
What are random variable?
If you randomly chose people from a list, then their hair color, height, weight, and any other data collected from them can be considered random variables.
What is the difference between quantitative and categorial variables?
Quantitative variables = numerical measures like height and IQ
Categorial variables = categories like eye color or music prefence
What is a quantitative variable?
numeric variables like height, age, weight…
What is a categorial variable?
category variable like blonde, listens to hip hop, female, yes…
What do we sometimes call a categorical variable?
qualitative variable
What is quantitative data?
The actual numbers gathered from each subject: 277 pounds, 67 beats per minute…
What is categorical data?
The actual individual category from a subject like “blue”, or “female”, or “sophomore”.
What is a random sample?
When you chose a sample by rolling dice, choosing names form a hat, or other REAL RANDOMLY generated samples. Humans cant really do this well without the aid of dice, calculator….
What is frequency?
how often something comes up
data or datum?
datum= singular data=plural
What is a frequency distribution?
a table, or chart that shows how often certain values or categories occur in a data set.
What is meant by relative frequency?
the PERCENT of time something comes up
How do you find relative frequency?
just divide frequency by TOTAL
What is meant by cumulative frequency?
ADD up the frequencies as you go. EX: you sell 25 pieces of candy, 10 the first hour, 5 the second, 3 the third, and 7 the last hour, the cumulative frequency would be 10,15,18,25
What is the difference between a bar chart and a histogram?
bar charts are for categorical data (bars don’t touch), It is the balancing point of the histogram.
What is the mean?
the old average we used to calculate, it is the balancing point of the histogram
What is the difference between a population mean and a sample mean?
population mean is the mean of a population so is a parameter. sample mean is the mean of a sample, so it is a statistic.
What symbols do we use for population mean and sample mean?
MU for population mean (parameter), x-bar for sample mean (statistic)
How can you think about the mean and median to remember the difference when looking at a histogram?
mean is balancing point of histogram, median splits the area of the histogram in half
What is the median?
The middlest number, it splits the area in half
What is the mode?
the most common, often used in categorical data
When do we often use mode?
With categorical variables. Not numerical
Why don’t we always use the mean, if we’ve been calculating it all of our life.
it is not RESILIENT, it is impacted by skewness and outliers.
When we say “the average teen”, are we talking about mean, median, or mode?
depends: for height mean, parental income, media, and music preference, mode.
