Week 9 and 10 Flashcards
What is descriptive statistics?
Obtained through descriptive statistical techniques that reduce data to manageable proportions.
What are some descriptive statistical techniques?
Measures of central tendency (mean, median, mode) Measures of variability (Standard deviations, range) Correlation Techniques (Scatter plots)
What are inferential statistics?
Statistical details that combine math and logic to test hypotheses about a population with sample data.
What are the levels of measurement?
Nominal, ordinal, interval, ratio. (Low to high)
What is nominal measurement?
Variables or events that are classified into categories. Ie. Gender, hair colour, marital status etc. Can be considered dichotomous or categorial.
What is ordinal measurement?
Reveals relative ranking of variables or events. Ie. Ranking, intervals not necessarily equal.
What is interval measurement?
Events or variables that are ranked on a scale with equal intervals between numbers.
What is ratio measurement?
Events or variables are ranked on scales with equal intervals and absolute intervals. Usually only achieved in physical sciences.
What is frequency distribution?
The number of times each event occurs is counted, data organized into groups then frequency is reported.
What is the mode?
The most frequent score.
What is modality?
The number of modes.
What is the median?
The middle score.
What is the mean?
The mathematical average of all the scores, used with interval/ratio level data.
What is a normal curve?
Unimodal symmetrical, mean, median, and mode are all the same.
What are measures of variability?
Statistical procedures that describe the level of dispersion in sample data.
What is range?
The distance between the highest and lowest score.
What is semiquartile range?
The range of the middle 50% of the scores. More stable than the overall range because it is less likely to be changed by a single extreme score.
What is a percentile?
Represents the percentage of scores that a given score exceeds.
What is a standard deviation?
Most frequently used measure of variability and based on the concept of a normal curve.
What is the z-score?
Used to compare measurements in a standard unit. Each score is converted to a Z score, to compare.
What are the 2 purposes of inferential statistics?
To estimate the probability that statistics found in the sample accurately reflect the population parameter and to test hypotheses about a population.
What is a parameter?
A characteristic of a population.
What is a statistic?
A characteristic of a sample.
What do inferential statistics allow researchers to do?
Allows them to make statements about the larger population from studying the sample.
What is the scientific hypothesis?
What the researchers believe the outcome of the study will be. H1.