Chapter 1- Introduction to Statistics Flashcards
What are descriptive statistics?
Organizes and summarizes data about a sample. Communicates observations but does not make assumptions or conclusions.
What are inferential statistics?
Draws conclusions about population based on information from a sample
What is a sample?
set of observations drawn from the population of interest. Statistic value
What is a population?
ALL possible observations. This is difficult to study so researchers focus on a sample of the population. Parameter value
What are variables?
Observations of physical, attitudinal, and behavioral characteristics that can take on different values
What are discrete observations?
SPECIFIC values. No other values can exist between these numbers. Whole numbers only. (letters in your name)
What are two types of discrete observations?
Nominal and Ordinal
What are nominal discrete observations?
Categories and names as their values (hair color, gender, flavors, race
What are ordinal discrete observations?
Rankings or order as their values (military, school, sports)
What are continuous observations?
observations that can take on a full range of numerical values; numbers out several decimal places (example: 12.839 seconds, or how tall you are)
What are two continuous observations?
Interval and Ratio
What are interval continuous observations?
Observations that have numbers as their values; the distance or interval between pair of consecutive numbers. The distance between the numbers are assumed to be equal. Time and distance are continuous interval observations but are also ratio because they have a true zero point that means something
What are ratio continuous observations?
The same criteria as interval continuous observations but the difference is the true, meaningful zero point (money, reaction time) You can make statements (twice as tall/ half as)
Examples of Variables using cookies: Nominal Ordinal Interval Ratio
Nominal: name of cookies
Ordinal: rank of favorite cookies
Interval: temperature of cookies
Ratio: how many cookies are left
Are nominal values always discrete?
Yes, always
Are nominal values continuous?
No, never
Are ordinal values always discrete?
Yes, always
Are interval values discrete?
Sometimes. There are 7 days of the week; the time between each day is the same (24 hours) . In addition, the days of the week can fit into a nominal category.
Are interval values discrete?
Sometimes. Personality and Attitude measure
Are interval values continuous?
Sometimes but yes
Are ratio values discrete?
Seldom
Are ratio values continuous?
Almost always
What are levels?
discrete value or conditions a variable can take on. Variables vary.
What are three types of variables?
independent, dependent, and confounding
What is an independent variable?
An independent variable has at least 2 levels that can be manipulated or observed to determine its effect on the dependent variable. (IV)
What is a dependent variable?
A dependent variable is the outcome variable that we hypothesize to be related to, or caused by, changes in the independent variable (DV)
What is a confounding variable?
A confounding variable that systematically varies with the independent variable so that we cannot logically determine which variable is at work ( soda has caffeine which can effect something but soda also has sugar which can effect something too. It difficult to determine which variable effect the dependent variable
What is a reliability?
Reliability is a measure that is consistent. Consistency–the same now, the same in an hour, year, ect.
What is validity?
Validity is a measure that measures what it is intended to measure. Bathroom scale measures weight, not fat
Can a test with poor reliability have high validity?
No. It should have both reliability and validity. It is not possible to measure what its intended to measure when the test itself produces varying results
Is a good variable both reliable and valid?
Yes
Does the independent value predict the independent value?
`Yes
What is hypothesis testing?
Hypothesis testing is the process of drawing conclusions about whether a particular relation between variables is supported by evidence.
What is a correlation?
A correlation is an associate between 2 or more variables. Making simple statement about associations.
What is an experiment?
An experiment is a study which participants are randomly assigned to a condition or level of one or more independent variables. Experiments attempt to explain a cause-effect relation between independent and dependent variable
What is correlational researach?
Research which random assignment of participants is not possible. Cannot make causal statements
What is random assignment?
Every participant in the study has an equal chance of being assigned to any condition. Able to make causal statements
