Psychological statistics unit 1 test

What is descriptive statistics?

statistics that summarizes data

What is inferential statistics?

statistics that uses data from a sample to make conclusions or predictions about a larger population.

What is a sample?

a subset of individuals selected from the larger population, which includes all possible cases of interest

What is a population

the entire group of interest for a study

What are variables?

characteristics or attributes that can take on different values

What are discrete observations?

variables that have countable values

What are continuous observations?

variables that can take on any value within a range

What does nominal mean?

categories without order

What does ordinal mean?

ordered categories, but intervals aren’t equal

What does interval mean?

equal intervals, no true zero

What does ratio mean?

equal intervals with a true zero

What are levels?

distinct values or categories a variable can take

What is a predictor variable?

the independent variable used to explain or predict another.

What is an outcome variable?

the dependent variable being measured

What is a confounding variable?

an outside factor that influences both predictor and outcome, potentially biasing results.

What is reliability?

the consistency of measurement

What is validity?

accuracy

What is correlation?

a statistical measure showing the strength and direction of the relationship between two variables.

What does an experiment do?

manipulates variables with random assignment

What does a Quasi-experiment do?

similar to experiments but lacks random assignment

What does a correlational study do?

examines relationships without manipulation.

What is random assignment?

random placing of participants into groups to reduce bias

What are ethical principles?

guidelines ensuring respect, beneficence, and justice in research.

What is a raw score?

an individual’s actual, unadjusted score

What is frequency distribution?

a summary of how often each value occurs

What is normal distribution?

a symmetrical, bell-shaped distribution of scores.

What is a frequency table?

a table showing counts of each value/interval

What is a histogram?

a bar-like graph showing frequency distribution of continuous data

What is an outlier?

an extreme value far from the rest of the data

What does skewness do? 

measures asymmetry 

What does kurtosis do?

measures peakedness or flatness

What does a positive skew have?

a long right tail

What does a negative skew have?

a long left skew 

What does platykurtic mean?

flat distribution

What does leptokurtic mean?

peaked distribution

Ceiling effect=?

many scores at the top

floor effect=?

many scores at the bottom

What does a scatter plot show?

shows relationship between two variables

What does a line graph do?

displays trends or changes over time

What does a bar graph do?

compares categories using bars

What does a pictorial graph do?

uses images/symbols to represent data

What does a pie chart do?

shows proportions as slices

What does a bubble graph do?

displays the relationships between three numeric variables from a dataset

What does a box and whiskers plot show?

distribution, median, quartiles, and outliers.

Mean

average of values

Median

middle value in ordered data

Mode

most frequently occurring value

Range

difference between highest and lowest values

Unimodal

distribution with 1 peak

Bimodal

distribution with 2 peaks

Multimodal

distribution with multiple peaks

What is variability?

the spread of scores in a dataset.

What is variance?

average squared deviation from the mean

What is standard deviation?

square root of variance; shows average distance from mean.

What does random sample mean?

each member of the population has an equal chance of being selected

What does convenience sample mean?

based on availability, not random

What is a snowball sample?

participants recruit others, often used for hard-to-reach populations

What is generalizability?

extent to which results apply to the larger population

What is confirmation bias?

tendency to favor information that confirms existing beliefs.

What is probability?

likelihood of an event occurring

What does research/alternative hypothesis do? 

predicts a relationship or difference

What is a null hypothesis?

a hypothesis that there is no significant difference between specified populations

What is a false positive

a positive result detected when none exists

What is a false negative?

a failure to detect a an effect when one exists