lec 1 Flashcards
what is a categorical variable?
qualitative characteristics without a numeral scale.
what is the significance of a NOMINAL categorical variable?
the lack of an order or hierarchy.
what is the significance of an ORDINAL categorical variable?
the possesion of an order or hierarchy
what is a numerical variable?
a variable with quantitative characteristics, typically relative to a numerical scale.
A continuous numerical scale is significant because of what?
it utilities divisible units, e.g. body temperature can be 1.5 and not just 1 or 2.
a discrete numerical scale is significant because of what?
it utilizes indivisible unis, e.g. the rank of a competitor in the Olympics, 1st, 2nd, 3rd, so on.
what are discriptive statistics?
statistics that tell us something about the values in a sample
what are the different ‘average’ values?
mean, median, mode.
what is a mean?
the sum of all the numeric responses divided by the total number of responses.
what is a median?
the middle number in the line of data, e.g. 1,2,3,4,5 the median would be 3, not 5 (the mean)
what is the mode?
the most frequent observation, e.g. 1,2,2,2,3,4,4,5 the mode would be 2
what are the ways that an observation can differ?
range, variance, and standard deviation
what is ȳ ?
the mean
if the mean, median, and mode are insignificantly different that would be called what?
a bell-shaped normal distribution
what is variance?
the sum of how every observation differs from the mean, squared
