Midterm 1 Intro to stats
Histogram
a bar graph depicting a frequency distribution
pie chart
a chart that shows the relationship of a part to a whole
bar chart
a chart with bars whose lengths are proportional to quantities
Standard Deivation
a computed measure of how much scores vary around the mean score
nominal measurement
a measure for which different scores represent different, but not ordered, categories
ratio measurement
a measure for which the scores possess the full mathematical properties of the numbers assigned
ordinal measurement
a measure for which the scores represent ordered categories that are not necessarily equidistant from each other
central tendency
a measure that represents the typical response or the behavior of a group as a whole (mean, median and mode)
null hypothesis
a statement or idea that can be falsified, or proved wrong
Correlation and Causation
correlation does not equal causation
Kurtosis
how flat or peaked a normal distribution is
statistical thinking
involves applying rational thought and the science of statistics to critically assess data and inferences. Fundamental to the thought process is that variation exists in populations and process data
negative skew
low outlier, median <mean
scales of measurement
nominal, ordinal, interval, ratio
relative frequency
number of times an allele occurs in a gene pool compared with the number of times other alleles occur
Central Limit Theorem
The theory that, as sample size increases, the distribution of sample means of size n, randomly selected, approaches a normal distribution.
interval measurement
a measure for which a one-unit difference in scores is the same throughout the range of the measure
mean
average
constructs
idea that cannot be seen or measured directly
range
the difference between the highest and lowest scores in a distribution
sampling distribution
the distribution of values taken by the statistic in all possible samples of the same size from the same population
effect size
the magnitude of a relationship between two or more variables
hindsight bias
the tendency to believe, after learning an outcome, that one would have foreseen it
anecdotal thinking
thinking that is based on hearsay rather than hard facts
continuous variables
can assume an infinite number of values between any two specific values. They are obtained by measuring. They often include fractions and decimals.
availability heuristic
estimating the likelihood of events based on their availability in memory; if instances come readily to mind (perhaps because of their vividness), we presume such events are common
variables
factors that can change in an experiment
type 2 error
failing to reject a false null hypothesis
positive skew
high outlier, mean > median
categorical variable
places an individual into one of several groups or categories
outcome
result
median
the middle score in a distribution; half the scores are above it and half are below it
quantitive variables
variables that can be counted or measured
data
Facts and statistics collected together for reference or analysis
error bars
Graphical representation of the variability of data
p-value
The probability level which forms basis for deciding if results are statistically significant (not due to chance).
Violin Plot
a graph that shows an approximation of the frequency distribution of a numerical variable in each group and its mirror image
variance
standard deviation squared
mode
the most frequently occurring score(s) in a distribution
type 1 error
Rejecting null hypothesis when it is true
interquartile range
The difference between the upper and lower quartiles.
alternative hypothesis
The hypothesis that states there is a difference between two or more sets of data.
bimodal distribution
a frequency distribution having two different values that are heavily populated with cases
scatterplot
a graphed cluster of dots, each of which represents the values of two variables
discrete variables
assume values that can be counted
line graph
A graph that uses line segments to show changes that occur over time
pictograph
A picture or drawing representing words or ideas
Boxplot
A plot of data that incorporates the maximum observation, the minimum observation, the first quartile, the second quartile (median), and the third quartile.
sample size
the number of times a measurement is replicated in data collection
absolute frequency
the number of times a score or value occurs in a data set
Operationalization
the process of assigning a precise method for measuring a term being examined for use in a particular study
confidence interval
the range of values within which a population parameter is estimated to lie
power
the rate at which work is done
standard error of the mean
the standard deviation of a sampling distribution
Multimodality
two or more communication modes to make meaning, e.g. image, spoken language, written language
Bootstrapping
using low-cost or free techniques to minimize your cost of doing business