GRE Psych: Research Methods, Stats, Test,
Measurements Questions and Answers 100%
Solved
variance square of the SD and describes how much each score varies from the mean.
calculated by subtracting the mean from each score, square each of them, then add them all
together, then divide by n
standard error of the mean tells us how "off" the mean might be in either direction
percentile tells us how many scores fall at or below that particular score in a normal
distribution
normal distribution
z-score calculates how many standard deviations above or below the mean a score is.
calculated by subtracting the mean from your score and dividing the difference by the SD.
mean of a distribution of z-scores is 0 and the SD of a distribution of z-scores is 1
,t-scores t-score distribution has mean of 50 and SD of 10.
t scores are a transformation of the z score (t= 10(z)+50)
correlation coefficients a type of descriptive statistic that measure the relationship
between two variables. they range from -1.00 to +1.00
the closer the value is to one, the stronger the relationship
DOES NOT INFER CAUSATION
positive correlation means that a change in value of one the variables is associated with a
change in the same direction of the value of the other variable (ex: if one goes up, the other goes
up)
negative correlation a change in the value ofone is associated with a change in the
opposite direction in the other variable (ex: if one goes up, other goes down)
scatterplot graphical representation of correlational data
, Pearson's r correlation coefficient a way of calculating/expressing correlations. values
range from -1 to +1 . -1= perfect negative relationship . +1= perfect positive relationship.
spearman r correlation coefficient another correlation used when the data is in the form of
ranks
regression allows you to identify a relationship between two variables and make
predictions about one variable based off another
factor analysis attempts to account for the interrelationships found among various
variables by seeing how they hang together
factor the one thing that his being measured by a cluster of highly correlated variables
significance test tries to determine that the hypothesis is consistent with the data by telling
us the probability that our observed difference betwween the two groups is due to chance.
Measurements Questions and Answers 100%
Solved
variance square of the SD and describes how much each score varies from the mean.
calculated by subtracting the mean from each score, square each of them, then add them all
together, then divide by n
standard error of the mean tells us how "off" the mean might be in either direction
percentile tells us how many scores fall at or below that particular score in a normal
distribution
normal distribution
z-score calculates how many standard deviations above or below the mean a score is.
calculated by subtracting the mean from your score and dividing the difference by the SD.
mean of a distribution of z-scores is 0 and the SD of a distribution of z-scores is 1
,t-scores t-score distribution has mean of 50 and SD of 10.
t scores are a transformation of the z score (t= 10(z)+50)
correlation coefficients a type of descriptive statistic that measure the relationship
between two variables. they range from -1.00 to +1.00
the closer the value is to one, the stronger the relationship
DOES NOT INFER CAUSATION
positive correlation means that a change in value of one the variables is associated with a
change in the same direction of the value of the other variable (ex: if one goes up, the other goes
up)
negative correlation a change in the value ofone is associated with a change in the
opposite direction in the other variable (ex: if one goes up, other goes down)
scatterplot graphical representation of correlational data
, Pearson's r correlation coefficient a way of calculating/expressing correlations. values
range from -1 to +1 . -1= perfect negative relationship . +1= perfect positive relationship.
spearman r correlation coefficient another correlation used when the data is in the form of
ranks
regression allows you to identify a relationship between two variables and make
predictions about one variable based off another
factor analysis attempts to account for the interrelationships found among various
variables by seeing how they hang together
factor the one thing that his being measured by a cluster of highly correlated variables
significance test tries to determine that the hypothesis is consistent with the data by telling
us the probability that our observed difference betwween the two groups is due to chance.
