Chapter 1: Statistics, Data, & Statistical Thinking Flashcards
What is statistics made up of?
Data
Define (Statistics)?
The science of collecting, organizing, analyzing, raw data, then presenting it so that it can be used to make predictions, decisions, or draw conclusions.
Explain the four step process of statistics.
1) Identify what you want to research: To do this a researcher must decide what questions they want answered, questions must be specific, this helps determine what population they will use to get their answers.
2) Collect data needed to answer questions: Samples are often used because populations are to big, if data is not collected probably conclusions drawn from data will be flawed.
3) Describe the data: Once the data is collected and analyzed it must be presented to others, the two ways of doing this is (Graphically or Numerically).
4) Perform Inference/ Draw Conclusions : Accurate results should be able to be extended to the entire population with a high level of confidence.
What is (Data)?
Info. that describes characteristics of an individual, can be (Numerical or Non-Numerical), eg gender is a variable, but the information that the gender is male or female are data.
What do we use data for.
We use data to draw conclusions, make decisions predictions, etc.
What is a (Data Item)?
One particular piece of data.
What is the difference between (Data & Information)?
1) Data: A collection of raw facts or numbers.
2) Information: Analyzed data, that holds a particular meaning.
What is a (Data Set)?
A collection of counts, measurements, etc. that’s collected while performing a study.
Describe the difference between (Descriptive and Inferential) statistics?
1) Descriptive: The use of (Tables/Graphs), to summarize data.
2) Inferential: Taking the results of a (Sample), & implying them to the (Entire Population).
What are the different types of data?
There are different types of data for each type of variable, thus qualitative variable corresponds with a qualitative data, the same is so for quantitative, discrete, or continuous data.
What is the (Probability Theory) based on?
(Inferential Statistics).
What is a (Population)?
The collection of all outcomes being studied, eg. all counts, measurements, etc. a population does not have to be large, eg. all the people in a city, everyone in a 20 member class, or all the corvettes made last year are all populations.
What is a (Parameter)?
A numerical measurement that describes a characteristic of a population, eg. 30% of Americans are overweight, 30% describes a characteristic of a population, thus it’s a (Parameter).
Why do we study populations?
To look for characteristics in the elements that make up the population, theses characteristics are called variables, eg. we may be interested in the average age, & education of all the women in a small town.
What is a (Sample)?
A part of a whole population, most populations are large, thus you can’t measure everyone or everything in a population, instead you measure a smaller piece, or sample.
What is a (Statistic)?
A numerical measurement that describes a characteristic of a sample, eg. 30% of the 400 people participating in the study were considered overweight.
What is the importance of a (Measurement)?
It assigns a value to a variable, eg. a group of male workers makes up a population, the variable is they are all male, if we want to assign a value to the variable, we take a measurement, for eg. age, height, weight, how fast they run a .25/mile, etc. then we assign a number/value to the variable.
What is a (Variable)?
Characteristics of an individual that is part of a population or sample, variables often change between individuals, eg. gender, height, age, etc.
What is one of the main goals of a researcher?
To help determine why certain variables are so different between individuals.
Name the 2 types of variables?
1) Quantitative: A variable that has a (Quantity), thus it consists of numbers, eg. tempt, weight, height, etc.
There are 2 types of (Quantitative Variables).
a) Discrete: Variables that have a definite value that can be counted, eg. number of children in a family, students in classroom, etc.
b) Continuous: Variables that have an infinite number of values, variable must be measured, eg. temp, height, weight, etc.
2) Qualitative: A variable having to do with (Qualities), thus it consists of words, eg. short, tall, male, female, etc. but if variable is presented as people who are 5’6” or under, it becomes (Quantitative Data).
Name the 4 levels of measurement that a variable can be measured in?
1) Nominal: A variable is nominal if it names, labels, or categorize data, nominal variables have no specific value, thus they can’t be ordered or ranked, eg. political parties, religions, marital status, etc.
2) Ordinal: An ordinal variable is the same as a nominal variable except it can be ordered or ranked, eg. letter grades, evaluations, etc.
3) Interval: Data with precise value, even if data lies between 2 measurements it’s exact value can be found, data can be ordered or ranked, this measurement has a zero, but it’s not a true zero, eg. IQ scores, temp, on a cold day a thermometer might read zero, but that doesn’t mean there is no temperature, thus it’s not a true zero.
4) Ratio: Has a true zero, true ratio is difference between the same variable of 2 different values, data can be ordered or ranked, eg the difference between 2 people’s weight, age, or height, eg. if one person is 3 feet tall and another is 6 feet tall the (Ratio) is the person that’s 6 feet tall is twice as tall as the 3 foot tall person.
What is a measure of (Reliability), & why is it important?
A statement that describes (Uncertainty) found in inference statistics, the only way to be 100% sure of a measure is to measure entire population, in most cases this can’t be done, thus there is always a (Degree of Uncertainty) when measuring a sample of a large population, eg. 60% of 1000 people sampled preferred Coke or Pepsi, the 60% doesn’t mean 60% of entire population prefers Coke, but 60% is within a certain range of entire population, let’s say 5%, thus (60% +/- 5%) is the number of reliability for the inferred stat.
What is a (Constant Sample)?
A sample that has all the same elements, eg. a sample of all women, men, lawyers, etc.
What type of variable are these level of measurements?
Both nominal and ordinal are qualitative variables, while interval and ratio are quantitative variables.