Vocabulary Flashcards
What is statistics?
The study of variability
What is variability?
How things are different between one member of the population to another.
What are 2 branches of AP STATS?
Inferential and descriptive
What are descriptive stats?
Describe the data that is collected. Pictures, summaries, mean median range etc
What are inferential stats?
While looking at the data, make connections to the bigger picture. (Small sample of soup represents the taste of the whole pot)
Compare descriptive and inferential stats
Descriptive: Explains and shows the data collected. Inferential: uses conclusions from the data to talk about the entire population
What is data?
Any collected information (typically from a study)
What is a population?
The group that is the focus of the study and is directly related to data collection.
What is a sample?
A subset of a population, taken in order to make inferences about the population. We take statistics from samples.
Compare population to sample
Populations are like a bundle of grapes while samples are only one grape each.
Compare data to statistics
Data is the small increments of information that is collected while statistics are summaries of the data written in a specific form
Compare data to parameters
Data is the small increments of information that is collected while parameter helps define how the data is categorized numerically.
What is a parameter?
A numerical summary of a population. Mean, median, range etc of a population.
What is a statistic?
A numerical summary of a sample. Mean, median, range, etc of a sample.
Dunkin donuts average wait time.
The parameter is the true average wait time at DD. This is a number you dont know. The statistic is 3.2 minutes, which is the average of the data you collected. The parameter of interest is the average wait time for all cars. The data is the wait time for each individual participant of the study.
Compare data-statistic-parameter using categorical example
Data are individual measures. Stats and parameters are summaries.
Compare data-statistic-parameter using quantitative example
Data are individual measures (how many seconds someone can hold their breath). 64, 80, 31. Stats and parameters are summaries. The avg time was 52sec.
What is a census?
A sample of an entire population, aiming to get a response from everyone.
Does a census make sense?
It is near impossible to take a census of a large population, but is more manageable when done with a small population size (Population of USA vs Math classP)
Whats the difference between a parameter and a statistic?
Both are a single number summarizing a group of much larger numbers.
Taking a random sample of 20 hamburgers from Five Guys and count the numbers of pickles. One of them had 9, the number nine from that burger would be called
A datum, or data value
Taking a random sample of 20 hamburgers from Five Guys and count the numbers of pickles. The average number of pickles was 9.5, the number 9.5 is considered a
Statistic
Taking a random sample of 20 hamburgers from Five Guys and count the numbers of pickles. You do this because you want to know the true average number of pickles on a burger, the true average is considered a
Parameter of interest
What is the difference between a sample and a census?
With a sample, data is collected from a small section of the population. A census attempts to gather data from the entire population.
Use the following words in a sentence
With a sample, you get information from a small part of the population. In a census, you get info from the whole population. You can get a parameter from a census but only a statistic from a sample.
If you are tasting soup, then the flavor of each individual thing in the spoon is _ , the entire spoon is a _. The flavor of all of that together is like the _ and you use that to _ about the flavor of the entire pot of soup which is _
If you are tasting soup, then the flavor of each individual thing in the spoon is data , the entire spoon is a sample. The flavor of all of that together is like the statistic and you use that to make an inference about the flavor of the entire pot of soup which is parameter
What are random variables?
If you randomly choose people from a list, their hair color, height, weight, etc can all be considered random variables
Whats the difference between categorical and quantitative variables?
Quantitative=Related to numbers. Categorical=categories, qualitative
Whats the difference between categorical and quantitative data?
Gathered measurements that are represented by numbers = quantitative. By words=categorical
Whats the difference between discrete and continuous variables?
Discrete can be counted (integers), while continuous could have decimal places.
What is a quantitative variable?
Related to numbers. Height, weight, age, etc
What is a categorical variable?
Hair color, eye color, etc
What is another word for categorical variable
Qualitative variable
What is quantitative data?
Actual numbers gathered from each subject
What is categorical data?
The individual category from a subject
What is a random sample?
Rolling dice, choosing names from a hat. Using chance to generate a sample
What is frequency?
How often something occurs
Data or datum?
Datum=Singular
Data=Plural
What is frequency distribution?
A table or chart that shows how often certain categories occur in a data set
What is meant by relative frequency?
The percent of time something happens. (frequency/total)
How do you find relative frequency?
Frequency divided by total
What is meant by cumulative frequency?
Add up frequencies as you go.
Make a guess as to what relative cumulative frequency is
It is the added up percentages that equals 100m percent at the end of the sample
What is the difference between a bar chart and histogram?
Bars=Categorical data, bars dont touch
Histo=Quantitative data, bars touch
What is the mean?
The average we use to calculate. Balancing point on the histogram
Whats the difference between a population mean and a sample mean?
Population mean is taken from a population and is a parameter. Sample, from a sample, 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 of the mean and median to remember the difference when looking at a histogram?
Mean is balancing point, median splits the graph in half
What is the median?
The middle most number (n+1/2)
What is the mode?
The most common or the peaks of the histogram.
When do we use mode?
With categorical variables
Why dont we always use mean?
It is not resilient, and is impacted by skewness and outliers
When we say “the average teenager” are we talking about mean median or mode?
It depends on what type of data is being collected.
