Topic 5: Standard Deviation (Measure of Variability) Flashcards
Measures of Dispersion (3)
Range
Quartile
Standard deviation
is a statistic that measures the dispersion of a dataset relative to its mean.
Standard deviation
is the most popular measure of dispersion.
Standard deviation
is denoted by Greek letter sigma
Standard deviation
is denoted by Greek letter MU
mean
Lower the value of ____ ___, lower the process of variability, thus data points are closer to the mean.
standard deviation
higher ____ ___ means that the data is more spread out or away from the mean
standard deviation
to determine How much data spreads from its “typical” value/Mean
The empirical rule
is the spread of your data from the lowest to the highest value in the distribution.
Range
Range is affected by the ____
Outliers
the 68–95–99.7 / three sigma rule, also known as the ___ __, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution
the empirical rule
It tells where concentrated our data sets is
Boxplot
68% of data points are within ___ standard deviation /so may 32% outside data points of __ standard deviation
1st
95% of data points are within ___ standard deviation /so may 5% outside data points of __ standard deviation
2nd
99.7% of data points are within ___ standard deviation /so may 1% outside data points of __ standard deviation
3rd
how many data points or “observations” you have
Count
is two ratios set equal to each other; comparison between two numbers.
proportion
Philippines-based company engaged in property-related activities, such as project design, construction and property management.
Megaworld corp.
When to buy stocks?
Determine using MEAN. If the data are closer to the mean, then its good to buy stocks. (3 standard deviation)
If data is high or low, we look to STANDARD DEVIATION.
Its up to us. More data, more chance we can predict if the stock will go up or down.
