Descriptive Statistics
A distribution of scores where the majority of the scores fall at the high end of the scale and the tail is drawn out towards the low end of the scale.
What is a negatively skewed distribution
The values "0" and "1" as they relate to the z distribution
What are the mean and standard deviation.
A sampling strategy that assumes I am putting each participant I select from the population for my sample back into the population for my next selection (sampling with replacement).
What is theoretical sampling?
The two parameters I need to know to calculate a z score.
What are the population mean and the population standard deviation?
The probability of rejecting the null hypothesis when the null hypothesis is true.
What is a Type I error? (also acceptable: What is alpha?)
This will increase if I multiplied a constant against every score in my distribution.
What is the variability? (what is the mean? is also acceptable)
The location of a z score of -1.8, relative to the mean in a z distribution.
What is, 1.8 standard deviation units to the left (i.e., less than) the mean.
Nn
What is the formula for determining the total number of samples that exist in the population of a set size?
What is the z score I need to determine statistical significance if I am doing a one-tailed test
When hypothesis testing, power is said to represent this:
What is the likelihood of finding an effect when an effect actually exists?
To get an unbiased estimator of the population's variance from a sample, I must divide the SS (sum of squares) by this.
What are the degrees of freedom (n-1)?
The value "1" as it relates to a normal distribution
What is the total area under the curve?
The existing mean (average) that the mean of my sampling distribution will have the same value as.
What is the population mean?
a z score of 1.96
What is the z score I need to determine statistical significance if I am doing a two-tailed test?
Because significance can be inflated (or impacted) by the sample size, this statistic should also be reported.
What is cohen's d?
A rule that states: 68% of scores fall within one standard deviation of the mean, 95% within two standard deviations and 99.7% within three standard deviations.
What is the empirical rule?
If you had a z score of +1.28 and a p-value of .10 (in the tail), your score would be at this "percentile"
What is the 90th percentile?
This theorem states that if I increase my sample size (n), the shape of my sampling distribution will become more normal and less variable.
What is the central limit theorem?
One test is used to compare a single score (X) against the population mean, while the other test is used to compare the mean of a sample (M) against the population mean.
What is the difference between a z test and a one-sample z test?
1 - alpha
What is the probability I have correctly retained the null hypothesis?
This descriptive statistic will always have a positive value
what is the standard deviation?
Approximately the % of scores falling ahead of a z score of +1 in a z distribution.
What is approximately 16%
σ/√n
What is the formula for calculating the standard error?
The part of the z score equation that changes when you compare a sample mean (M) against the population instead of just a single score (X).
What is the denominator?
When the overall effect size decreases, power will change in this direction.
What is a decrease?