week 2 variables Flashcards
what is reliability
when data is accurate and consistent
what is validity
when data measures what its supposed to measure
types of variables
categorical(qualitative) and numerical(quantitative)
two types of categorical data
nominal and ordinal
example of nominal data
eye colour, defined categories
example of ordinal data
low, medium, high
good, great, better
two types of numerical data
discrete and continual
example of discrete data
no of people in a family, how many text messages sent yesterday, show sizes, whole numbers
examples of continuous data
time spent in a checkout line, just because a number is not in your data doesnt mean it wasnt possible
is ranking implied in nominal data
no
is ranking implied in ordinal data
yes, eg poor, fair, good, excellent
what is an interval scale
an ordered scale, difference between measurements is a meaningful quantity but have no true 0 point eg age brackets, the 0 point implies they wouldnt exist
what is a ratio scale
an ordered scale, difference between measurements is a meaningful quantity and it DOES have a true 0 point
what is populatios
contains all the items or individuals of interest you seek to study
what is a sample``
contains only a portion of the population of interest
