psychometrics

• coding of categorical data
• (i.e. males=1 females=2)

• ranked order of data
• (i.e. class rank from highest to lowest)

• ranked order with the difference between values
• (i.e. 2, 3, 4 have an interval of 1 between each and no absolute value)

• comparative data that is interval-level with an absolute zero
• (i.e. person a is 5' and person b is 4' then person a is 1' taller than person b)

the variance between individual scores/scale values are normallu distributed in the general population (i.e. 95% distributed symetrically under a bell curve)

• Reports that data found would occur due to chance X times out of 100.
• Correspond to p-values (i.e. 5 out of 100 times due to chance = .05)

a distribution of actual data or test scores (mean, SD, variance)

• theoretical distibutions with mean, variance, & SD.
• used to set alpha levels for a statistical test; used to determine acceptance or rejection of the null hypothesis.

• describes the strength and direction (vector) of a linear value between two variables.
• if one variable rises in value and the second rises proportionally then it is a positive manner correlation. However, if one variable rises in value and one decreases in value the the correlation is negative manner.

requires the indication of one variable is dependant on another variable (a predictor).

• standardized score with a mean of zero and a SD of 1.
• z score = (raw score - mean)/SD

• converted z score.
• New distribution score = (z score x SD new) + New Mean.

"an idea or perception resulting from a synthesis of sense impressions."

• occures when the construct evaluates what they are supposed to.
• when imperfections occur there are two types of imperfections: deficiency (when a measure does not cover the domain of a construct in its entirety); and contamination (when a measure contains material that should not be a part of the construct).