# Research Quiz

 Standard Deviation average deviation from the mean in the originalunit of measurement.  Normal distributions the mean, mode, and median are the same. Bell-shaped & symmetrical Positively-skewed distribution majority of scores on the lower end of range (the mean  is more positive than mode and median). Negatively-skewed  majority of scoreson the higher end (mean is more negative than mode and median. Reliability consistent,true.  Is a psychometric indicator ofquality of an instrument.  Consistencywhen test is repeated.  Reliability coefficients can be calculated to provide an indication ofthe amount of measurement error. Example: on a 0-1 scale, .8=80% reliability.  Based on the amount of consistency betweentwo sets of scores. Correlation the statistical technique used to calculate thisconsistency Positive correlation scores are consistent in the same direction Negative correlation scores are consistent in different directions, so as scores on one test increase, scores on another decrease Standard Error of Measurement (SEM) helpful in interpreting an individual’s score.  Provides an estimation of the range of scores that would be obtained if someone took an instrument over and over again.  Takes reliability into account. Validity concerns what an instrument measures and how well it does it.  Instruments are not valid, uses of instruments are. *Reliability is a prerequisite to validity.  If there is too much error, the instrument can’t measure anything consistently. Convergent evidence positive relationship of instrument with other variables with which it should theoretically be related.  *High=if it agrees Discriminant evidence no relationship or negative relationship of instrument with variables from which it should differ in these ways.  *Low=it disagrees. (Happiness/stress/anxiety) Norm-referenced in comparison to others Norming group group who took the instrument to which others’ scores are then compared Mode most frequent score in a distribution Median the score where half the people had a score below it and half had a score above, evenly dividing the scores in half Mean average of the scores Frequency Distribution Can interpret scores more accurately if scores are tallied this way.  (Ex: clas has 30 students, these are their scores....) Normal curve largest mumber of cases cluster in center (68)Bell-shpaed Scales of Measurement Nominal, Ordinal, Interval, Ratio Nominal Numbers are used to classify and identify personsNumbers are substituted for names or verbal labels Ordinal Assigns numbers in rank order Interval Helps when interested in differences or intervals between things Ratio Only scale where you can say "twice as...x"Ratios between the umbers assigned to the person or objectCorresponds to the ratios between the attributes measured in these thingsAddresses issues of relative size, weight, speed, etc. of 2 objects Authorjojossu ID166740 Card SetResearch Quiz DescriptionFor upcoming quiz Updated2012-08-30T00:52:25Z Show Answers