Variables
This type of variable is manipulated by the researcher
Independent variable
Conducted in a real life environment but still manipulates the IV
Field experiment
Every member of the population has an equal chance of being selected.
Random sampling
Each participant takes part in only one condition of the IV.
Independent groups
Name one measure of central tendency
Mean
Median
Mode
A researcher measures how long people can balance on one foot after drinking an energy drink What is the DV?
Time balancing on one foot
This type of experiment occurs in a controlled lab setting
Lab experiment
You pick every 5th person from a list. Sampling type?
Systematic
What is a non directional (two tailed) hypothesis?
A hypothesis that does not predict the direction of results
Which measure is most affected by outliers?
The mean
A study finds boys scored higher than girls in a memory test, but the boys were tested in the morning and girls in the afternoon. Whats the confounding variable.
Time of day of testing
Compare ecological validity and control in lab and field experiments
Lab = high control, low ecological validity Field = higher ecological validity, lower control
Stratified sampling
Dividing the population into groups and sampling proportionally from each group
Students who sleep more than 7 hours score higher on exams is an example of a
Directional hypothesis
If height increases as weight increases, this is a what type of correlation?
Positive correlation
Extraneous variable
A variable that interferes with the relationship between IV and DV, influencing the outcome
Why does a natural experiment have high ecological validity but low control?
Because it occurs in real-life settings (realistic) but the researcher cannot control all variables.
Strength and weakness of volunteer sampling
Strength = participants are motivated Weakness = may not represent the population
Strength and weakness of repeated measures.
Strength = controls participant variables Weakness = order effects
A researcher finds –0.85. What type of correlation is this?
Strong negative correlation.
Give an example of an IV and DV in a memory experiment
IV = word list difficulty DV = number of words recalled
other examples allowed
Name one strength and one weakness of lab experiments
Strength = high control of extraneous variables Weakness = low ecological validity
Which sampling method gives everyone an equal chance, but is time-consuming to organise?
Random sampling.
Which design best controls participant variables? Explain
Matched pairs = controls participant differences without order effects.
Difference between standard deviation and range?
Range = spread from lowest to highest SD = average spread of scores around the mean.