Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
stats exam 1
| Term | Definition |
|---|---|
| mean | x bar, sensitive to outliers, sum of individuals divided by total (n), the numeric average |
| median | the point that divides a distribution in half, not sensitive to outliers, order from low to high and find middle value to calculate |
| mode | the most frequently occurring value, not sensitive to outliers |
| standard deviation | sx, measures the average distance from the mean of the observations, square root of variance |
| gee whiz graph | misleading, does not start at 0 |
| skew left | tail on left side of graph, mean decreases |
| skew right | tail on right side of graph, mean increases |
| outliers | observations that lie further from the center |
| absolute figure | can be interpreted without any context, has some intrinsic meaning |
| relative figure | has meaning only in comparison to something else |
| normal distribution | data that are symmetrical around their mean in a bell shape |
| n | total individuals/observations |
| Σ | sigma, sum of/add |
| Xi | value of each individual |
| data | pieces of information |
| dataset | spreadsheet/table containing data |
| individuals | observations, cases, objects described by a database |
| variables | a characteristics of an individual, varies (has more than one value or attribute), each column in a dataset represents a unique variable |
| variation | differences across individuals |
| categorical variables | not numeric in a way that permits sensible mathematic operations (ex. political views, grades A, B, C), pie charts, bar graphs |
| quantitative variables | individuals have numeric value (ex. # of states visited, grades 100, 90, 80), histograms, time plots |
| in a spreadsheet... | each column is a variable, each row is an individual |
| how to make a pie chart | list all the values (categories) a variable takes, then count the # of individuals that take on each value |
| how to make a bar graph | bars do not touch, x-axis has categories, y axis has frequency/%, identify the values of the variable, count up # of individuals in each value, draw & label axes and values |
| time plot purpose | allow use to see change and trends over time |
| measures of central tendency (averages) | allow us to find and describe the average or typical tendency in a distribution, mean, median, and mode |
| median location formula | M=(n+1)/2 |
| bimodal | two values of mode tied for most frequently occurring |
| no mode when... | there is not one number that occurs more than the others |
| when will mean, median, and mode be the same value | symmetrical distribution (bell curve) |
| histogram | a vertical bar graph showing the distribution of a quantitative variable, bars touch |
| how to create a histogram | identify range, pick amount of bars (6-20), find bar width, create intervals starting from lowest value, count the # of individuals in each interval, and draw |
| range of a histogram | max-min |
| bar width formula | range/# of bars |
| x axis | variable values/ intervals |
| y axis | frequency, number of individuals |
| spread of a histogram | the min and max intervals |
| sampling goal | generalize to the larger population of interest from samples |
| population | the entire set of individuals/things we are interested in |
| population parameter | # that comes from a population, often impossible to calculate parameters |
| sample | a subset of the pop from which we generalize |
| statistic | a # that comes from a sample |
| simple random sampling | everyone in pop has the same probability of inclusion |
| probability based | each member of pop has an known chance of inclusion in sample |
Created by:
23cryera