PSYCHOLOGY 270- RESEARCH METHODS
Cronback's Alpha - Answers- measures internal consistency: average correlation
between all scores on all paired questions on a survey
Split half reliability - Answers- scores are similar in different sets of questions on a
survey that address similar topics
• Internal Consistency - Answers- reliability tests relationships between scores on
different items of a survey.
• Testing effects - Answers- Occur when participants are tested more than one and it
affects later testing
• Convergence bias: - Answers- sampling error that occurs when the sample chosen to
complete the survey does not provide a good representation of the population
• Nonresponse Bias: - Answers- Individuals chosen for the sample do not respond,
biasing the sample
• Attrition/mortality- What kind of threat? - Answers- participants choose not to compete
the study- they do not come back to finish ie. drop out
Internal and External Validity threat
• Test-Retest Reliability: - Answers- the scores were consistent over time
• Social Desirability Bias - Answers- Participants responded according popular social
beliefs
• Criterion-Related Validity - Answers- determining the validity of the scores of a survey
by comparing it to scores and established measures
• Closed-ended Response - Answers- Likert scales, too little response= cause bias, too
many= confusing although increases validity, make sure there are equal number
• Open-ended - Answers- participants can put whatever they want to put as their
answers
Type 1 Error - Answers- Null hypothesis is true but one rejected the null hypothesis
Type 2 Error - Answers- Null Hypothesis is false and one failed to reject the null
p-value is ≤ alpha - Answers- reject null; significant accept alt.
p-value > is alpha= - Answers- cannot reject null
, • P-value - Answers- probability level associated with an inferential test that indicates
the likelihood of obtaining the data in the study when the null hypothesis is true
• Alpha level - Answers- the probability level used to indicate a cutoff probability that will
allow rejection of null hyp.
• Two- tailed hypothesis - Answers- considers both directions, (memory changes over
time); verses one-tail is when it is directional (older people have lower memory scores
than young...)
Predictor variable- Scatter Plot - Answers- predict the score of another variable
Outcome variable-Scatter Plot - Answers- variable being predicted by the predictor
variable
Variability - Answers- Range, SD, Df
Range: - Answers- difference between the highest and the lowest score, crude because
it ignores everything in the middle of the distribution
Standard Deviation - Answers- average distance of the scores and the mean in a given
distribution, squaring that value and adding them up dividing by degrees of freedom
Degrees of Freedom - Answers- n-1: number of scores that can vary in the calculation
of statistics
Measures of Central Tendency - Answers- Mean, Median and Mode
• Sampling Error - Answers- the difference between observation in the sample and the
population, sample value is unlikely to hit the population value
Simple Random Sample
(Say Adv and dis) - Answers- Each member of the population has an equal chance of
being selected using random sampling
Adv: Reduce Sample Error
Dis: Difficult to ensure each member of a large pop can be chosen in a sample
Cluster - Answers- Clusters of individuals are identified and then a subset of clusters is
randomly selected to sample from
Adv: makes it easier to choose members randomly from small clusters to better
represent the population
Dis: Ignore segments of people
Stratified Random Sample
Adv/dis - Answers- Proportion of group in the sample is equal to the proportion of the
group in the population using random sampling
Cronback's Alpha - Answers- measures internal consistency: average correlation
between all scores on all paired questions on a survey
Split half reliability - Answers- scores are similar in different sets of questions on a
survey that address similar topics
• Internal Consistency - Answers- reliability tests relationships between scores on
different items of a survey.
• Testing effects - Answers- Occur when participants are tested more than one and it
affects later testing
• Convergence bias: - Answers- sampling error that occurs when the sample chosen to
complete the survey does not provide a good representation of the population
• Nonresponse Bias: - Answers- Individuals chosen for the sample do not respond,
biasing the sample
• Attrition/mortality- What kind of threat? - Answers- participants choose not to compete
the study- they do not come back to finish ie. drop out
Internal and External Validity threat
• Test-Retest Reliability: - Answers- the scores were consistent over time
• Social Desirability Bias - Answers- Participants responded according popular social
beliefs
• Criterion-Related Validity - Answers- determining the validity of the scores of a survey
by comparing it to scores and established measures
• Closed-ended Response - Answers- Likert scales, too little response= cause bias, too
many= confusing although increases validity, make sure there are equal number
• Open-ended - Answers- participants can put whatever they want to put as their
answers
Type 1 Error - Answers- Null hypothesis is true but one rejected the null hypothesis
Type 2 Error - Answers- Null Hypothesis is false and one failed to reject the null
p-value is ≤ alpha - Answers- reject null; significant accept alt.
p-value > is alpha= - Answers- cannot reject null
, • P-value - Answers- probability level associated with an inferential test that indicates
the likelihood of obtaining the data in the study when the null hypothesis is true
• Alpha level - Answers- the probability level used to indicate a cutoff probability that will
allow rejection of null hyp.
• Two- tailed hypothesis - Answers- considers both directions, (memory changes over
time); verses one-tail is when it is directional (older people have lower memory scores
than young...)
Predictor variable- Scatter Plot - Answers- predict the score of another variable
Outcome variable-Scatter Plot - Answers- variable being predicted by the predictor
variable
Variability - Answers- Range, SD, Df
Range: - Answers- difference between the highest and the lowest score, crude because
it ignores everything in the middle of the distribution
Standard Deviation - Answers- average distance of the scores and the mean in a given
distribution, squaring that value and adding them up dividing by degrees of freedom
Degrees of Freedom - Answers- n-1: number of scores that can vary in the calculation
of statistics
Measures of Central Tendency - Answers- Mean, Median and Mode
• Sampling Error - Answers- the difference between observation in the sample and the
population, sample value is unlikely to hit the population value
Simple Random Sample
(Say Adv and dis) - Answers- Each member of the population has an equal chance of
being selected using random sampling
Adv: Reduce Sample Error
Dis: Difficult to ensure each member of a large pop can be chosen in a sample
Cluster - Answers- Clusters of individuals are identified and then a subset of clusters is
randomly selected to sample from
Adv: makes it easier to choose members randomly from small clusters to better
represent the population
Dis: Ignore segments of people
Stratified Random Sample
Adv/dis - Answers- Proportion of group in the sample is equal to the proportion of the
group in the population using random sampling
