Distributions-and-Zs1
What type of score identifies the location of raw score in a distribution?
Z-score
There are three basic "scales of measurement". What are they?
Nominal, ordinal, equal-interval/ratio
A psychologist records the number of drinks consumed in a week. Measurement scale is?
EQI/ratio
t and F-tests require the DV be measured on what type of scale?
EQI/Ratio
Students receive services if their score on an ADHD screening lies +1 SD or more above the mean. What % is this?
About 16% (14+2 ... OR 50-34)
A distribution where scores pile-up at the high end is:
Negatively skewed
Adding, subtracting, multiplying, dividing by constant is what type of transformation?
A linear transformation
Another name for a Z-score is?
A standard score
A ___ test is used with two groups; ______ used with three or more.
t-test; ANOVA/F
Tabachnick&Fidell consider an outlier to be beyond?
+/- 3.29 SDs from mean
In a normal distribution, what % of scores lie between -1 and +1 SDs?
34 + 34 = 68
In a positively skewed distribution, the mean is [less than or greater than] the median?
Greater
In hypothesis testing, where do we typically “draw the line” for statistical significance?
.05
Participants are categorized by Type of Disorder (Anxiety, Depression, Substance). Disorder is measured on
Nominal Scale
A gifted program considers students w/ IQs > 120. If IQ normally dist. w/ M = 100 and SD = 15 what Z-score is 120?
120-100/15 = 1.33
Which measure of central tendency is best when data are skewed?
Median
A distribution is negatively skewed. Transforming each raw score to a Z-score will normalize the distribution. T or F?
False (a linear transformation)
The M of a set of scores is 3.29. If 3.29 is subtracted from every raw score in the set, the new mean will be?
0 (zero)
p is a measure of _____ significance. Effect size is a measure of _______ significance.
statistical; clinical/practical
Converting raw scores to Z-scores is a type of [linear or non-linear] transformation?
Linear
In a normal curve, what % of scores lie below a Z-score of 1.00?
34+50=84
The mean and SD of a set of Z-scores will always be
zero and one
This is also called?
Centering
Difference between st. dev. (SD) and standard error?
SD: Variability in sample of Xs; Standard Error: Variability in sampling dist. of Ms
In a normal curve, what % of scores lie within +/-2 SDs of the mean?
About/Appx. 95%