Distributions
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
This type of error occurs when a researcher misses a true effect
Type II
In a normal distribution, what % of scores lie between -1 and +1 SDs?
34 + 34 = 68
As N increases, the standard error?
Decreases
In hypothesis testing, where do we typically “draw the line” for statistical significance?
.05
d-family measures of effect size assess
Differences between means (SD units)
We generally like power to be?
.80
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 (subtracting a constant from every score decreases mean by same amount)
The F-ratio is a ratio of which two types of variability?
Between / Within
This type of error occurs when a researcher incorrectly claims a treatment works
Type I
What type of score identifies the location of raw score in a distribution?
Z-score
This theorem tells us what the characteristics of a sampling distribution will be
Central Limit Theorem
This is also called?
Centering
Which one of these is influenced by trxt effect
Between
This is the probability one will identify a true effect that actually exists
Power
In a normal curve, what % of scores lie below a Z-score of 1.64?
95% (draw it out)
The standard deviation of a sampling distribution is known as
The standard error
The t-test equation is a ratio of
Diff between two means divided by st. error
R-family measures of effect size assess
Proportion of variability
Power is usually estimated before a study is carried out to determine
N