stats other stuff Flashcards
(34 cards)
how do you calculate a marginal distribution
take every value in a column or row of a table and add them together, then divide by the table’s total
how do you calculate a conditional distribution
take one specific variable and divide it by its category (ex: girls with blue eyes divided by girls, when men with different colored eyes are also included in the table)
what is a confounding variable
an outside variable that can cause disruption in a distribution’s results
what type of graph is good for categorical data
bar graphs and pie charts
what type of graph is good for quantitative data
dot plots
why is it important to start the y axis of a graph on 0
starting the y axis on a higher number may cause exaggerated results
what acronym should you use to describe a distribution’s properties
SOCS (shape, outliers, center, and spread)
how do you interpret a stem and leaf plot
Digits in the stem represent the numbers first digit(s) and leafs represent the numbers second digit
what type of data uses histograms
quantitative
what is the difference in bar graphs and histograms
histograms are for quantitative data and their bars represent a range of data, but bar graphs are for categorical data and their bars represent specific values
what is the difference in X bar and Mu (mean variables)
X bar represents the sample mean, while Mu represents the population mean
which type of distribution is described using mean and standard deviation
Normal distribution (symmetric)
what type of distribution is described using median and IQR
A skewed distribution
what percentile is Q1
25th
what percentile is Q2
50th
what percentile is Q3
75th (meaning 75% of the data values fall below the value of Q3)
how do you calculate the high outliers in a data set
low outliers occur if points are higher than what you get when you calculate Q3 + (IQR x 1.5)
how do you calculate the low outliers in a data set
low outliers occur if they are less than what you get when you calculate Q1- (IQR x 1.5)
what elements does adding and subtracting affect in a distribution
mean and median but not spread (IQR or standard deviation)
what acronym should you use to describe correlation and scatterplots
DUFS (direction, unusual points, form: whether its linear or not, and strength)
what is the meaning of r2
how much of the data can be accounted for or explained by the independent variable in a distruibution
what does correlation require
that both variables are quantitative
how do you calculate residuals
Actual value - predicted value
a census…
collects data from every individual in a population
