Experiments
A teacher tests whether background music affects concentration by giving one group music and another silence. What's the IV & DV?
IV: background music (music vs silence)
DV: concentration
A researcher studies helping behaviour in a real street setting but manipulates how many books a person will drops. What type of study is this?
Field experiment
A graph shows both variables increasing together.
Positive correlation
What is opportunity sampling?
Participants are selected because they are available.
Best graph for categories
Bar chart
A researcher wants to investigate whether listening to music affects concentration in students. Operationalise the DV “concentration.”
Ex: Concentration measured by the number of correct answers on a 10-minute test
The same participants complete a memory task in both quiet and noisy conditions, is the example for...
Repeated measures design
Students who sleep late at night tend to score higher.
Identify the direction
Negative correlation
A researcher selects student IDs from a list. What type of sampling is this?
Random sampling
When can we use scatter graph
A researcher studies relationship between two variables
A researcher uses “loud music” vs “soft music” as IV levels.
Explain one problem and suggest an improvement
A memory study is conducted in a controlled classroom with fixed instructions.
Identify the type of experiment AND explain one strength
Lab experiment
Strength: high control → high reliability
A study shows a strong negative correlation between stress and sleep.
Explain what this means
As stress increases, sleep decreases strongly
Give 1 example of volunteer sampling
e.g. Participants sign up through an online form.
A researcher records the number of words recalled by five participants in a memory test:
12, 15, 9, 14, 10
Calculate the mean number of words recalled.
Mean = 12
A researcher wants to investigate whether Screen time affects memory performance. Suggest both control & experimental conditions of the IV
Control: No screen time
Experimental: 5 hours & 10 hours screen time
What are order effects? And give 1 Example
A participant performs a task twice and improves due to practice effect. Or, A participant performs a task twice and get worse due to fatigue effect
A researcher finds a strong correlation between video games and aggression.
Explain one limitation of this finding
Cannot establish causation
A researcher selects names using a random number generator.
Explain why this is useful
Reduces bias → more representative
Scores: 5, 6, 7, 8, 50
Which measure is most appropriate and why?
Median → not affected by outlier
A researcher studies whether exercise affects mood. Create the directional hypothesis
People who exercise more will have better mood than those who exercise less.
Participants complete both conditions: with caffeine and without caffeine.
Identify the design AND explain one strength and one weakness
Repeated measures
Strength: controls participant variables
Weakness: order effects
A study finds a correlation between ice cream sales and crime rates.
Explain the weakness of third variable problem and an example of it
e.g. Hot weather could affect and increase both data, to see the causal relationship
A study uses only students from a top academic class.
Identify the problem AND explain it
A dataset has a large range and high SD
Explain what this tells us AND one limitation