REVIEWER IN RESEARCH
I. Measures of Central Tendency
Central Tendency
-descriptive statistic
-measures of the average
-middle
Mean
-average
-uses all score in the data set
-affected by anomalies
Formula:
x=∑x
n
Median
-middle value
Formula:
~
x=n
2
*n=number of data in a given set
Mode
-most common value
-greatest frequency
Formula:
^
x=¿
most frequent
II. Measures of Variability
Range
-the simplest measure of
variation to compute
-the difference between the
smallest and the largest value in a
given set
Standard Deviation
-most commonly used
measure of variation
-indicates how closely the
values of a given data set are
clustered around the mean.
-the positive square root of
the variance
-denoted by
σ
Formula:
σ=
√
∑
(
x−μ
)
2
N
¿
¿
Variance
-denoted by
σ2
Formula:
σ2=∑
(
x−μ
)
2
N
¿
¿
Unbiased Estimator
-a statistic whose value
approximates the expected value of
a population variance
Formula:
δ2=∑
(
x−x
)
2
n−1
Where
x
= sample mean
N= sample size
Shortcut formulas
-they save time when
repeated subtracting and squaring
occur in the original formulas
δ2=n∑x2−
(
∑x
)
2
n
(
n−1
)
¿
¿
δ
=
√
s2
