Descriptive Statistics
This transformation of a data set affects the mean and standard deviation but not the shape of the distribution.
What is multiplying or dividing by a constant?
If two events A and B are mutually exclusive, this must be true about P(A and B).
What is P(A and B) = 0?
This principle divides participants, ensuring that each participant has an equal chance of being in any treatment group.
What is random assignment?
This is the probability of rejecting the null hypothesis when it is false.
What is power?
This is the description of a scatterplot.
What is direction, unusual features, form, and strength?
This measure is resistant to outliers and used to summarize the center of a skewed distribution.
What is the median?
The rule used to find the probability of A or B occurring.
What is P(A) + P(B) - P(A and B) = P(A or B)?
This sampling method involves the division of a population into separate groups, called strata, based on shared attributes or characteristics. Within each stratum a simple random sample is selected, and the selected units are combined to form the sample.
What is a stratified random sample?
This distribution is used instead of the normal distribution when estimating means and σ is unknown.
What is the t-distribution?
This gives the direction and quantifies the strength of the linear association between two quantitative variables.
What is the correlation, r?
This statistic changes if you remove the maximum value in a right-skewed data set.
What is the mean (and standard deviation)?
This is a range of values likely to contain the true population parameter.
What is a confidence interval?
This type of variable is not the explanatory or response variable but can affect the outcome of an experiment.
What is a confounding variable?
Name two conditions that must be checked before performing a one-sample t-test for a population mean.
What are randomness, normality, independence (10%)?
This is the definition of bias.
What is occurs when certain responses are systemically favored over other?
When a distribution is symmetric and unimodal, this is the best measure of center.
What is the mean?
The Law of Large Numbers states that as n increases, this happens to the sample mean.
What is it approaches the population mean?
When a sample is comprised entirely of people who choose to participate, the sample will typically not be representative of the population because of this type of bias.
What is voluntary response bias?
The probability of observing a test statistics as extreme as, or more extreme than, the one calculated from the sample, assuming the null hypothesis is true.
What is the p-value?
What is when 68% of the observations are within 1 standard deviation of the mean, 95% of observations are within 2 standard deviations of the mean, and 99.7% of observations are within 3 standard deviations of the mean? (68-95-99.7)
This tells you how many standard deviations a value is from the mean.
What is a z-score?
This theorem allows us to use a normal distribution to model the sampling distribution of the sample mean when n≥30.
What is central limit theorem?
The difference between blocking and stratifying is that blocking is used in ________, while stratifying is used in ________.
What is experiments; sampling?
The procedure to choose to compare the means of two-independent populations when you know the population standard deviations and sample sizes are greater than 30.
What is a two-sample z-test?
An example of a confounding variable in a study investigating the effect of exercise on blood pressure.
What is age, fitness, medicine, diet, etc.?