Statistics and brain scans Flashcards
EEG electroencephalogram
measures electrical activity on surface of brain with electrodes on scalp due to nerve cells producing electricity when firing.
CAT computerised axial tomography scan
rotating x-ray tube around head producing series of x-ray pictures. Computer combines pictures into one.
MRI magnetised resonance imaging
A neuroimaging technique that produces an image of the brain without x-rays but with magnetic fields and radio waves.
DTI diffusion tensor imaging
maps neuronal pathways and measures structural connectivity in the human cortex in vivo.
PET positron emission tomography
small amount of radioactive glucose injected in bloodstream then used by computer imaging to produce colour portrait of brain displaying active areas (nerve cells use glucose for energy).
Percentile
Percentage of data that falls below the value. 50th percentile is the median. Quartiles and quintiles are quarters and fifths or 25th and 20th percentile.
Inferential statistics
Assess whether results obtained with a sample reflect whole population.
Statistical significance
Likelihood results of a study occurred by chance. Measured with p-value, less than 5% or p<0.05 is statistically significant.
t-test
Compares mean scores of two groups to test for statistical difference.
ANOVA analysis of variation
Same as t-test but for three groups or more.
Chi square test (X2)
Used when both IV and DV are categorical to test if there is a significant association between them measured with Pearson’s r= co-efficiency.
Effect size
Magnitude of experiment effect or strength of relationship measured with Cohen’s d= effect size.
Descriptive statistics
Researchers summarise data in a readily understandable form.
Frequency distribution
Shows how frequently participants received each score.
Measures of central tendency
Mean (average of all scores), Mode (most common score), and Median (score that falls in the middle of distribution, good if there are extreme scores in data).
