Introduction to research design and data Flashcards
Describe the 3 variable types
IV: what changes
DV: what we measure
CV: what stays the same
whats a control condition
a separate condition that helps us understand the role of IV and help rule out alternative explanations for results
What are between subject study designs
- independent group design
- each participant contributes one data point
- avoids some participant effects
- takes longer and less powerful due to individual differences
describe within subject designs
- repeated measures design
- each participant contributes multiple data points
- accounts for individual differences
- order and fatigue effects (counterbalancing)
describe matched pairs design
- participants matched across conditions to try account for differences
- often too difficult to accurately match people
What are extraneous variables
- not controlled
- affect the DV
- noise, weather etc
What are confounding variables
- EV that vary systematically with the IV to influence the DV (variance in the DV can appear to be due to the IV when it’s not)
Describe 2 different data types
categorical - nominal or ordinal
numerical - interval or ratio
what are descriptive statistics
mean
median
sd
range
how do you find out the SD?
SD / square root of sample size
How do you find the z score?
(score - mean) / SD
what is a Z score
- a standardised score that represents a datapoints relationship to the mean of a group of values
- it is useful for comparing scores between participants or across conditions
What does a normal distribution look like?
bell curve
what does a negatively skewed distribution look like?
mean, median mode
tail starts on the left
what does a positively skewed distribution look like?
mode, median, mean
tail end on the right
