Chapter 3 ( SEMI FINALS) Flashcards
is the practice or science of collecting and analyzing numerical data in large quantities,
Statistics
is a central or typical value for a probability
distribution.
Central tendency
It may also be called a center or location of the distribution.
Central tendency
The most common measures of central tendency are the
arithmetic mean
the median
the mode
is the sum of all measurements divided by the number of observations.
Arithmetic Mean
simply an average of the data.
Mean
is the “midpoint” of our data that separates the upper and lower half of the data set.
Median
the most frequent value in the data set.
Mode
This is the only central tendency measure that
can be used with nominal data, which have purely qualitative category assignments
Mode
of a distribution is typically contrasted with its dispersion or variability;
Central Tendency
also called
variability, scatter, or spread
Dispersion
is simply the difference between the smallest and largest data point in the set.
Range
is the average of the absolute deviations from a central point.
Mean Absolute Deviation
It is a summary statistic of statistical dispersion or variability.
Mean Absolute Deviation
is another way of measuring the spread between numbers in a data set.
Variance
it measures how far each number in the set is from the mean.
Variance
is simply the square root of the Variance.
Standard Deviation
It is the most commonly used
measure to express dispersion.
Standard Deviation
are cut points dividing the range of a probability distribution into continuous intervals
with equal probabilities, or dividing the observations in a sample in the same way.
Quantiles
Dive the data into 4 parts
Quartiles
divide data into 10
Deciles
divide into 1% segments
Percentiles
Quartiles are
often used as a measure of spread of the data in what is called the
interquartile range (IQR
simply the difference between the third quartile and first quartile.
Interquartile Range
is a way of standardizing scores on the same scale by dividing a
score’s deviation by the standard deviation in a data set.
A z-score, or standard score,
it measures the number of standard deviations
a given data point is from the mean.
Z-score or Standard Score
represents the ratio of the standard deviation to the mean,
Coefficient of Variation
allows investors to determine how much volatility, or risk,
is assumed in comparison to the amount of return expected from investments.
Coefficient of Variation
refers to distortion or asymmetry in a symmetrical bell curve, or normal distribution, in
a set of data.
Skewness
means the Mean is greater than the Median
Positive Skew
means the Mean is less than the Median.
Negative Skew
is a statistical measure that expresses the extent to which two variables are linearly
related
Correlation
meaning they change together at a constant rate
Correlation
It’s a common tool for describing simple
relationships without making a statement about cause and effect.
Correlation
Colloquially, measures of central
tendency are often called
Averages
