Know-How: Don´t be afraid of statistics!
If you start a survey not only the survey is important but also
the result. To process the results, statistic values are of great
importance. Even if statistics seem to be complicated, they are,
in fact, simple. Statistics turn huge amounts of numbers into a
manageable amount and define probabilities for "events"
that have not been analyzed.
Among others statistical values, values like count, frequency,
median, mode, standard deviation, absolute deviation, range, variance,
kurtosis, poisson and skew are of great interest. This values are
explained below:
Count: Here the number of people who answered
is displayed.
Frequency: Here the percentage of people who answered
is displayed.
Average: The average is the sum of values, divided
by the number of values.
For example, if you ask seven people, how many people are employed
in their company, and you get the answers 10, 25, 30, 35, 40 and
50, then the average is 31,4 (10 + 25 + 30 + 30+ 35 + 40 + 50 =
220 / 7 = 31,4).
Median: The median is the value in the center
after all the values have been sorted in ascending order. In the
above example the median is 30. If you have an even number of values,
you can choose one of the values in the center. If this values are
not the same you take the average of these values.
Mode: The mode is the most represented value.
In our example the mode is 30 ( it just happens to be the same value
as the median).
Standard deviation: The standard deviation curve
shows how the scores are spread out. A high standard deviation indicates
that values deviate more from the mean - are more spread out - than
samples with a smaller standard deviation.
Absolute deviation: Here the absolute values of
the differences (and not the differences) from the mean are summed,
because adding the positve and negative values of differences in
a distribution from its mean, will always be 0. The absolute value
of negative 5 (-5) is 5, just as the absolute value of positive
5 is 5.
Range: The range is the difference between the
highest and lowest data point. For example, looking at the answer
values 10, 25, 30, 35, 40, 50, the range is 50 - 10, which is 40.
Variance: The variance is the spread of the values
from the mean. The square root of the variance is the standard deviation
(see above).
Kurtosis: The kurtosis is a measure of the peakedness
or flatness of a distribution. The kurtosis for normal distribution
is 0. The more the values deviate positive or negative from 0, the
more definitive is the measured skew. The kurtosis helps you to
find out the "right" distribution.
Poisson: The poisson distribution is used to find
the probability of the number of events that occurr in a specific
time period.
Skew: The skew relates to the asymmetry of a distribution
around its average. Positive skew means that the distribution has
a long tail in the positive direction (to the right). Negative skew
means that the distribution has a long tail in the negative direction
(to the left).
Using these values mass appearances can be analyzed and presented
in numbers. By means of numbers, it is easier to compare results.
A numerical value is clearer than thousands of values that may come
out when launching a survey. It is also obvious that the average
is more significant than a number of numerical values. For example,
if you ask 30 people for their age, you get a better idea if you
know the average value, than having 30 numbers in front of you.
So don´t be afraid of these complicated statistical values,
because they help you to analyze and evaluate your survey results.
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