1 Flashcards
(48 cards)
What is Statistics(textbook)?
The science of collecting, organization, summarizing, analyzing, and making inferences from data.
What are the two major branches of statistics we will study this year?
Inferential and Descriptives
What is variability?
Differences…how things differ. There is variability everywhere…We all look different, have different preferences….Etc
What are Descriptive Stats?
Numbers and pictures that describe nature of a data set, provide info about data that is present.
What are Inferential Stats?
Making inferences…saying what is actually going on in the population, making predictions, using statistics to estimate parameters.
Compare descriptive to inferential.
Descriptive seeks to tell u about what is in the data at hand, inferential reaches out to the world at large.
What is data?
Any collected information. Generally each little measurement.
What is a population?
The group you are interested in. Sometimes it’s big, like “all teenagers in U.S. “Other times it is small like “ Mr littlefield’s fifth period class”. You calculate parameters from populations.
Comparable population to sample.
Population are generally and samples are small subsets of there population. We talk samples to make an inference about what we think is true on the population. We use statistics to estimate parameters.
What is a parameter?
A numerical summary of a population. Like a mean, median, range… of a population.
What is a statistic?
A numerical summary of a population. Like a mean, median, range… of a sample.
What is a sample?
A subset of a population, often taken to make inferences about the population.
What is statistics(Nystrom’s def)?
The study of variability.
We are curious about the average wait time at a Dunkin Donuts drive through in your neighborhood. You randomly sample cars one afternoon and find the average wait time is 3.2 minutes. What is the pop ulation parameter? What is the statistic? What is the parameter of interest? What is the data?
The parameter is the true ave rage wait time at that Dunkin Donuts. This is a number you don’t have and will never know. The statistic is “3.2 minutes .” I average of the data you collected.
Compare DATA STATISTIC PARAMETER 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-STATISTIC-PARAMETER 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 large group of numbers…But pppp parameters come from pppp populations… sss statistics come from ssss statistics.
What is the difference between a sample and a census?
With a sample, you get information from a small part of the population. In a census, you get info from the entire population. You can get a parameter from a census, but only a statistic from a sample.
What are random variables?
If you randomly choose 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 categorical variables?
Quantitative variables are numerical measures, like height and IQ. Categorical are categories, like eye color and music preference.
What is the difference between discrete and continuous variables?
Discrete can be counted, like “number of cars sold” they are generally integers (you wouldn’t sell 9.3 cars), while continuous would be something like weight of a mouse… 4.344 oz.
What is a quantitative variable?
Quantitative variables are numeric like: Height, age, number of cars sold, SAT score.
