Terms
A bias caused by a number of people who did not respond to the survey
Non-Response Bias
the population is divided into strata and a random sample is taken from each stratum
stratified sample
measures an outcome of a study
response variable
The objects described by a set of data
Individuals
You decide to take a survey at your high school. You place everybody in random groups to carry out the survey. Which method are you using?
cluster sample
A type of response bias where the question is stated in a certain way to achieve a desired result
Wording Bias
The Hypothesis that states there is no difference between two or more sets of data in a significance test
Null hypothesis
The probability of getting a result at least as extreme as the result given from the test. The lower the value the stronger the evidence.
p value
May help explain or influence changes in a response value
explanatory variable
The arithmetic average of a distribution.
Mean
An error that occurs when a researcher concludes that the independent variable had an effect on the dependent variable, when no such relation exists; a false positive.
Type I Error
all possible outcomes of an experiment
sample space
A mean of 0 and standard deviation of 1
Standard normal distribution
shows the relationship between two quantitative variables measured on the same individuals
scatter plot
individuals are randomly assigned to groups but are not randomly selected from the population.
Experiment
Statistical procedures used to describe characteristics and responses of groups of subjects
Descriptive Statistics
Experimental results caused by expectation alone
Placebo effect
Takes numerical values for which it makes sense to find an average.
quantitative data
The range of percentage points in which the sample accurately reflects the population, the range surrounding a sample's response within which researchers are confident the larger population's true response would fall.
margin of error
The standard deviation of the difference between two random variables
What is the square root of the sum of the variances of the two random variables?
what the difference between an observed value of the response variable and the value predicted by the regression line
residual
A common form of blocking for comparing just two treatments
matched pairs
A variable tells us what values the variable takes and how often it takes these values
distribution
When your discovered p-value is less than your alpha (.05 if not given). States that chance alone would rarely produce an equally extreme result.
statistical significance
Interpret: A z-score of -3.45
The data value is 3.45 standard deviations below the mean