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