Pharm- stats Flashcards
what is the definition of statistics?
the science of assembling, classifying, tabulating, and analyzing data of a numerical nature to present significant information about a given subject
what are two categories of statistics?
descriptive statistics
statistical inference
what is the definition of descriptive statistics?
a way of summarizing data from a population or a sample
what is the definition of statistical inference?
comparison of data, extrapolation
why should vets learn about statistics?
to be able to criticize scientific papers and their statistic analyses
where does choice of treatment, business management and grade of cancers information come from?
reading papers, which are updated about new techniques, treatment and/or diagnosis
definition of data
collection of information (numbers, scores, measurements)
a set of values of qualitative or quantitative variables
define qualitative data
non-numeric data (data can’t be counted)
define quantitative data
numeric data (data can be counted)
define observation
entities whose characteristics we measure
define measurement
assigning numbers to observations according to pre-set rules
ex) measurement of Heart Girth
define variable
a measured characteristic that can have various values or levels
define variable
quantitative
can have only certain values (usually whole numbers)
define continuous variable
quantitative
can have any value
define categorical variable
equivalent or qualitative
non numerical
define binary variable
have only 2 possible values
usually 1/0 or yes/no
define ordinal variable
qualitative
non numerical but considered to have an order
define nominal variable
qualitative
categorical with no order
what are two types of variables?
qualitative
quantitative
what are 3 types of qualitative variables?
binary
nominal
ordinal
what are 2 types of quantitative variables?
discrete
continuous
define population
an entire group of observations that (might) have at least one characteristic in common
define sample
a group of elements selected from the population
define parameter
a characteristic of a population
define statistic
a characteristic of a sample
what are two methods to summarize data?
text
graphical
what are two types of text summary of data?
tabular frequency
numerical
define absolute frequency
number of observations
define relative frequency
proportion of observations
define cumulative frequency distribution and when should it be used?
frequency of the scores including the frequency of the previous scores
used for quantitative/ordinal variables only
what is the graphical representation of data called and what is it a representation of?
histogram
representation of the frequency distribution
what are two types of distribution of a histogram?
random distribution
pattern- skewed distribution
what are the 2 parameters to describe quantitative data?
location parameter (measure of central tendency)- same pattern, different location dispersion parameter- same location, different pattern
what are the 3 measures of central tendency?
mean
median
mode
define mean, median, mode
mean: the average of a data set
median: the middle value of a data set
mode: the most frequent value of a data set
what are 3 main measures of variability?
range
variance & standard deviation
interquartile range
define range
the difference between the highest data value and the lowest value
define variance & standard deviation
measure how far the distribution is spread out from the mean
define interquartile range
the range between the 1at quartile and the 3rd quartile
what is the % of values within 1 SD, 2SD and 2SD of the mean in normal distribution
68%
95%
99.7%
define standard deviation
variability of the variable distribution for the sample or for the population
define standard error and what does it allow?
standard deviation of the variable mean
allows to estimate the confidence interval of the mean
what is the difference between a histogram and a bar plot?
a histogram is used to represent grouped frequency data (quantitative)
bar plot is used to represent qualitative data
what is a barplot/histogram used for?
to plot absolute and relative frequencies of qualitative/quantitative variable
what is a pie chart used for?
to plot the relative frequencies of categorical variable
what is a boxplot used for?
to plot the distribution of quantitative variable
what is a scatter plot used for?
to plot 2 quantitative variables
what is a line plot used for?
to plot quantitative variable in time
