statistics Flashcards
what is descriptive stats
describes what data has to say
organizes summaries and communicates the numerical observations
can be numerical or visual
population vs sample
population is = all of uvic students
sample = the 100 uvic students
cna’t make generalizatons off of a smoke
what is Inferential stats
allows tests of hypothesis
can study samples then make generalizations about a popualtion
sampling error refers to
samples are not always representful of a full population
numbers vs numerals
numerals - code that represents qualatative category
numbers - a real number
data vs datum
datum - single observed value
data - multibe observed values
discrete vs continuous
discrete - numbr of huamns in a room - cant have 3.5 humans
continuous - infinite number of possibel vlaues that can fall between any two observed values - height, age, time
ind vs dependant variable
ind - type of drug consumed
dep - affects of drug on person
score is
either interval or ratio
nominal
categories equal to each toher
ordinal
categories in order - one is more than the other but we don’t know how much more
interval
can measure how much more of each one is
has no true 0, can’t use for ratios
ratio data
knows how much more of
has a true 0, has ratios
can say smth is twice as long/large
when doing calculations, compute to __ decimal places
for final answer report to _ sig digits beyond original value - so we look at third number to see whether to round up or down
calculations - report to 4-6 decimal places
final answer - report to 2 sig digits beyond original valye - look at 3rd number to see to round up or down
39.79463 is 39.79
what are parameters
descriptors about the popualtion
examples of interval
farenheight, celsuius, date, time of the day
frequency table
shows
is x ind or dep variable
the number of ind’s in each category
x - independant variable
what order do numbers go in on the X part of freq table
bottom to top
lowest number at bottom, highest one at top
if there is 0 for a categoroy do we still list the x value and 0 on the freq table
yes
upper case sigma Σ means what
sum
N means what (freq table)
the total number of scores
what are the 5 measures of variability
Range
SIQR
Median Absolute Deviation
Variance
Standard Deviation (linked to variance)
variability
there are _ ways to measure it
average distance of scores from the centre - how they are spread out
5 ways to measure it
list what variability measures are most suitable for each NOIR
N - none
O - range, siqr, mad
Interval and Ratio - range, siqr, mad, variance, sd
variance and SD are _________
different parts of one equation
the only measure of central tendencay we can use for Nominal
Mode - the most common category
which x value has the highest number on the f column
or MO
