exam one Flashcards
sample
SUBSET of the population to gain insight about the population
population
TOTAL set of measurements (unknown)
sample statistic
descriptive stats, sample of data (sample mean, sample variation, sample SD)
population parameters
descriptive measure of population (mean, variation, SD)
statistical inference
estimation, confidence intervals, hypothesis testing
histogram
bar chart to show quantitative data
frequency (f)
how many of each “class”
relative frequency
probabilities: f/n
cumulative frequency
∑fi
cumulative relative frequency
∑fi/n = 1
quantitative data
numerical quantity
qualitative data
quality or characteristic
discrete measurements
only a finite or countable number of variables
continuous measurements
infinite values corresponding to points on a line interval
four levels of measurement
nominal, ordinal, interval, ratio
nominal
lowest, only used to classify or categorize
ordinal
rank/order
interval
distances b/w consecutive numbers have meaning, data always numerical, zero is not fixed (temperatures)
ratio
highest, absolute zero, the ration of two numbers is meaningful (height, weight, time, volume)
measures of variation
range, variance, standard deviation, mean absolute deviation
mutually exclusive
two or more events cannot occur at the same time; if one happens, the other cannot
statistically independent
the occurrence of one event doesn’t affect the probability of another
statistically dependent
changes in result of another variable
null hypothesis (H0)
assumed to be true until proven otherwise (being tested)
alternative hypothesis (Ha)
accepted as true if H0 is disproved
p-value
probability calculated from a test statistic that measures whether it is likely/unlikely
small p-value
unlikely
standard error of the mean
how different the population mean is likely to be from the sample mean
