Descriptive Statistics and Law of Large Numbers Flashcards
If we want to represent an entire distribution or at least some special characteristic of it, by means of a single, summary numerical index or a pair of such indices, what is this called?
Descriptive Statistics
What is the two major categories of summary statistics (descriptive statistics)?
- Indices of location 2, Indices of dispersion
Indices where some nameable part of a distribution is on the horizontal axis are?
Indices of location
This tells us how spread out the distribution is according to some criterion
Indices of dispersion
What is another term for regularity?
The mean
What is another term for diversity?
Variance
What is statistically described via regularity?
– pattern, consistency, shape
– regularity allows for existence of science
– measures of central tendency or location
What is statisically described by diversity?
– differences, uniqueness, individuality
– diversity makes for interesting science
– measures of dispersion
What are the different types of indicies of location?
- Mode
- Median
- Mean
What is the crudest index of location?
Mode
Define the mode?
the value that occurs with the greatest
frequency.
In other words, the value that is
possessed by the greatest number of units
in the set.
If a data set has two or more values may be tied for the
greatest frequency, what is this called?
Biomodal (2)
Multimodal (2+)
What is the value of the middle unit?
Median
How do we define the median?
N units arranged in a line in order
of increasing value, the median is the middle one between the highest and lowest value
note that this is unit middle NOT value
How do we calculate the median if we have an even # of units in a data set?
Average the 2 middle values
What is the 50th percentile?
Median
How do we determine a percentile value rank given a data set?
i.e. we are given the data set and the percentile and we are trying to find the value that corresponds to the percentile
THIS IS A BONUS QUESTION NOT COVERED IN THE LECTURE
Given a score and a data set how do we determine the percentile rank of a score?
THIS IS A BONUS QUESTION NOT COVERED IN THE LECTURE