Statistics
2.
Random Variables
The values which vary
There will be some chance associated with all possible outcomes
There is no pattern for outcome
1.
Graphical Representation
barplot / dotchart
representing each datapoint with a bar/dot respectively
Histogram
frequency distribution
The entire range is split into classes / bins / intervals
count of the data points falling in each interval/bin is plotted
boxplot
100% of data is represented using 4 quarters
Min / lower extreme
Q1 / First quartile / lower quartile
lower 25% of data lies between min and Q1
Q2 / Median
Q3 / upper quartile / 3rd quartile
IQR = Q3 - Q1 = box region
IQR has middle 50% of data
Q4 / upper extreme
between Q4 and Q3 - upper 25% of data
Outliers
any data point which lies beyod = Q+/- 1.5(IQR)
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Data :
Qualitative
categorical data which cannot be quantified
Quantitative
Continuous datatypes
data that can be represented on a decimal scale
Discrete datatypes
data that cannot be represented on a decimal scale
Measurements
Nominal
Labeling the data
Ordinal
giving order/direction/preference
Interval
quantifying the magnitude of the order/direction
comparision is done on local scale
Ratio
quantifying the magnitude on a global scale
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Probability distribution
Graphical representation of probabilities of events
X-axis = Events
Y-axis = Probabilities
Based on data type of X
Continuous Prob. Dist.
Discrete Prob. Dist.
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