Stats Quiz 5/29

Question Answer
Cross-sectional study data collected at a fixed point in time
Retrospective (case controlled) study data collected about the past (records, interviews, etc)
Prospective study data collected in the future from groups sharing common factors
Randomization Randomly select subjects for different groups
Replication Results can be repeated on more than one subject to reach the same result
Blinding Subjects do not know which group they are in (placebo)
Double blinding Researcher doesn't know which group the subject is in
Placebo effect An untreated subject reports and improvement in symptoms
Confounding occurs in an experiment when you are unable to distinguish the effects of different factors
Completely Randomized Experimental Design Assign subjects to different treatment groups through random selection
Randomized Block Design Form blocks of subjects with similar characteristics
Randomly assign subjects within the blocks
Rigorously Controlled Design Carefully assign subjects to different treatments so that subjects for a particular treatment are important to the researcher.
Matched Pairs Design Compare exactly two treatment groups with subjects that are matched to have similar characteristics
Sampling error Results do not match results in whole population
Nonsampling error Occurs when data is incorrectly collected or analyzed
Center representative value for “the middle” of the data set
Variation measure of the amount of data that values vary
Distribution shape of the spread of the data
Outliers Sample values that lie far away from the majority of other values
Frequency Distribution also known as a frequency table, it shows how the data set is partitioned over various categories given by listing the categories and the number of data values in each category
Lower-class limits Smallest numbers that can belong to different classes
Upper-class limits Largest numbers that can belong to different classes
Class boundaries Centers in the gaps between upper and lower class limits of successive classes