Intro to statistics 1 - types of data and summary statistics Flashcards
What can statistics be used to objectively evaluate?
accuracy of estimates of means and population sizes
probability of differences or trends being other than just due to sampling error or natural variability
What is a population? (statistics)
A set of similar items or events which are of interest for a specific question or experiment
What 2 types of statistical population is there?
Group of actually existing objects
or
Hypothetical potentially infinite group of objects
What is a sample? (statistics)
A set of data collected/selected from the population
What can individual sample components be referred to as?
sample points, sampling units or observations
What is probability?
The measure of likelihood for a specific event to occur based on statistical analysis of sample data.
What is data? (statistics)
individual pieces of information used for statistical analysis, raw info which observations are collected
What are the main types of data?
Discrete
Continuous
Catergorical
What is discrete data?
Data/variables which only take a finite number of values and cannot
be subdivided
What is an example of discrete data?
minerals in a rock sample
What is continuous data?
Data/variables which can take an infinite number of values (data can be subdivided infinitely)
What is an example of continuous data?
Height
What is categorical data?
Data/variables which are mutually exclusive (i.e. can only have one state)
What is an example of categorical data?
On or off
What are the 2 categories of data?
Quantitative
Qualitative
How can quantitative data be split?
Ratio
Interval
How can qualitative data be split?
Nominal
Ordinal
What is ratio data/ ratio scale?
Data with a defined, numeric scale AND with an absolute/natural zero (i.e., values cannot be negative)
What is an example of ratio data/ ratio scale?
Weight (150g)
What is interval data/ interval scale?
Data with a defined, numeric scale but WITHOUT an absolute zero (i.e., values can be positive, negative, and zero)
What is an example of interval data/ interval scale?
Celsius scale
What is nominal data/ nominal scale?
Discrete, mutually exclusive data with no numerical order/meaning
What is an example of nominal data/ nominal scale?
Rock type (magmatic/ sedimentary)
What is ordinal data/ ordinal scale?
Discrete, mutually exclusive data that can be ranked according to some characteristic
How are units of measurement decided and by what system?
Determined by type of measurement
System- systeme internationale d’unites 1948
What is precision?
the variability of results (i.e. how close to each other repeated measures are)
What is accuracy?
the closeness of results to the ‘true’ value
What is the central tendency?
single value that attempts to describe and
summarise a data set by identifying the central position within the data
What is variance in data?
how the data are dispersed
How is variance of a data set calculated?
calculated as the average of the squared differences from the mean.
What is standard deviation? (variance)
The standard deviation is the
square root of the variance. It indicates how much the data is spread on average
How do you get the difference when calculating variance?
You must calculate the mean so you get the difference between the observed values and the average
What is a sampling error?
The difference between the calculated mean and the true mean of the population
What is frequency?
how often individual data values appear in the data set
How is frequency data usually presented?
In a histogram
What are examples of frequency and distribution?
Aggregated distribution
Random distribution
Even distribution
What is aggregated distribution?
Population clumped in one area
What is random distribution?
no set pattern to population distribution
What is even distribution?
The population is equally distributed throughout the environment
