2 - Measures of locations and spread Flashcards
How is the lower quartile of discrete data found?
n/4
if position is a whole number, then take value between this and the next position
if not a whole number, round up and take this position
What does using grouped frequency tables rely on?
Interpolation
What is interpolation?
Assuming data values are evenly distributed within each class
How is the upper quartile found for grouped continuous data?
n/4th data value
How are variance and standard deviation estimated when using a grouped frequency table?
using midpoint if each class interval
How is the mean of coded data found?
mean(y) = (mean(x) - a)/b
How is the standard deviation of coded data found?
sd(y) = sd(x) x a
In a histogram, what does area represent?
Frequency