MATH
indicate how spread the values or how far away these values tend to fall from the center, particularly the mean.
Measures of Variability or Dispersion
are the most commonly used measures of variability
range, variance, and standard deviation
the difference between the highest and lowes values
Range
is the square root of the variance
sample standard deviation
the average of the squares of the deviation of each given value from the mean.
Sample Variance
what is X
individual values
expresses the amount of variation or dispersion relative to the mean. Used when comparing the variability of the sets of data with different standard deviations and different means
Coefficient of Variation
is the degree of symmetry or departures from symmetry of a set of data
Coefficient of skewness
it is similar in shape to a normal distribution except that it is not symmetrical
Skewd distribution
sk means?
coefficient of skewness
if the value of mean is equal to the median mode, then the coefficient of skewness is zero, what does it implies?
normal or symmetrical distribution or bell-shaped curve
if the value of mean is greater to the median mode, then the coefficient of skewness is greater than zero, what does it implies?
positively skewed distribution and has a longer right tail
if the value of mean is less than the median mode, then the coefficient of skewness is less than zero, what does it implies?
negatively skewed distribution and has a longer left tail
A procedure may be usedto determine the relationship between to variables is?
correlation
a statistical tool to measure the association of 2 or more quantitative variablels.
correlation
The statistics used to describe the degree or magnitude of realtionship between variables is called?
Correlation coefficient (r)
describe as perfect, high, moderate or low.
degree or magnitude
classified as positive correlation, negative correlation and zero correlation
direction
Types of correlatiob may be classified in terms of?
magnitude or direction
there is a direct relationship between variables
positive correlation
one high values and low values on the second variable
negative correlation
most widely used measure of correlation which was developed by Karl Pearson. Used for interval and ratio (numerical) type of data
Pearson product moment correlation coefficient (r)
used to find out if there is a significant relationship between 2 variables of ordinal type.
Spearman-rank order correlation coefficient (p)
used to make predictions about a single value.
linear regression
exist when values in one variable tend to score neither symmetrically high nor symmetrically low in the other variable
no (zero) correlation