Environmental Data Analysis BC ENV 3017
Data summaries
Basic graphical representations of data as used in the ozone lab
There are different ways how to plot data
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time series - entire time period vs. just the hours
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bar graph vs. line plot (example: precipitation)
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cyclicity, period
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make the graph long, focus on a few days of data at the time
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histograms
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bins, frequency (array formula!), radar diagram
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example: income in US
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scatter plots
Descriptive statistics (qualitative, we will discuss the details later)
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count
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average (arithmetic mean)
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the mean is the sum of a set of numbers divided by how many there are.
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median
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the median is the number in the middle of a set of numbers; that is, half
the numbers have values that are greater than the median, and half have
values that are less.
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mode
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the mode is the most frequently occurring, or repetitive, value in
an array or range of data.
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minimum
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maximum
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range
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standard deviation
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the standard deviation is a measure of how widely values are dispersed
from the average value (the mean).
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variance
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another measure of the spread of the data.
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kurtosis
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kurtosis characterizes the relative peakedness or flatness of a distribution
compared with the normal distribution. Positive kurtosis indicates a relatively
peaked distribution. Negative kurtosis indicates a relatively flat distribution.
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skewness
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skewness characterizes the degree of asymmetry of a distribution around
its mean. Positive skewness indicates a distribution with an asymmetric
tail extending toward more positive values. Negative skewness indicates
a distribution with an asymmetric tail extending toward more negative values.