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Research & Statistics
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Terms in this set (17)
independent variable
the variable believed to cause some variation in another variable (an intervention or treatment)
hypothesis statement
statement of relationship between 2 or more variables. independent stated 1st then direction of impact then dependent variable
dependent variable
the variable whose variation must be explained- what you are studying (a particular behavior such as alcohol abuse)
nominal level of measurement
basic, categorical, ex male/female, religions
ordinal level of measurement
ranks, ie freshman, sophomore, junior, senior
interval/ratio
continuous data, can do mathematical operations
reliability
consistency in the measurement of a variable- measuring the same subjects under the same conditions at a later time should yield the same results
validity
extent to which a measure reflects the true characteristic of what the researcher is trying to measure
measure of central tendency
mean, median, mode- used to represent all the scores in a group, gives concise description of the performance of the group as a whole, allows comparisons w/in and between groups
mean
sum of the scores divided by the number of scores- average. use when the most stable measure is wanted and when other statistics are to be computed.
median
the midpoint of a series of hierarchically ordered scores. half the scores fall below and half fall above. use when the exact midpoint is wanted when there are extreme scores (ie when the distribution is skewed) provides least amt of info
mode
the score of measure occurring most frequently, use when a quick and approximate measure is all that is wanted, when the typical value is wanted
range
the lowest to highest score
standard deviation
most stable measure of variability. a standardized measure which shows the degree to which scores are spread or dispersed around the mean
correlation
must be between 1 and -1. perfect correlation=1, perfect negative correlation= -1.
normal curve
standard deviation= 68% 2 standard deviation= 95%
null hypothesis
must be disproved at the .05% probability level for hypothesis to be accepted
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