User's Manual

BrailleNote Apex QT User Guide
8-209
MEAN as represented by the Greek letter symbol, mu, italicized x with a bar above it, m or mean
values: For a data set, the mean is the same as the average. It is the sum of all the values divided by
the number of values. For example, the mean or average of 2, 3, 3, 5, 7 and 10, is 30 divided by 6,
which is equal to 5.
MEDIAN: In statistics, a median is the middle number in a group of numbers. At most, half the
numbers in the group have values that are greater than the median, and half have values less than
the median. For example, the median of 2, 3, 3, 5, 7 and 10, is equal to 4.
MODE: The mode is the value that has the largest frequency. For example, the mode of 2, 3, 3, 5, 7,
and 10, is 3. Note that there may be more than one mode in the data set or no mode at all if every
number occurs to the same frequency. Where there is more than one mode, use the Frequency Order
in review mode to view them.
SAMPLE SIZE as represented by the letter N:
The sample size is the total number of values in the data set.
POPULATION STANDARD DEVIATION as represented by sigma, sigma with subscript n, or
italicized x with sigma and subscript n:
The population standard deviation is a measurement of the variability of data in a population. In
statistics, Population refers to a set of potential measurements or values, including not only cases
actually observed but those that are potentially observable.
SAMPLE STANDARD DEVIATION as represented by italicized s, sigma with subscript n minus
1, or italicized x with sigma and subscript n minus 1: The sample standard deviation is a
measurement of the variability of data in a sample. A sample differs from a population in that it is
the part of a statistical population which is actually observed. Note that this type of standard
deviation is the most commonly requested when the standard deviation is required in an equation.
SUM OF VALUES as represented by capital sigma italicized, italicized x followed by subscript n:
The sum of values is the total you get when all the individual values in the data set are added
together.
SUM OF THE SQUARE OF VALUES as represented by capital sigma italicized with italicized x
followed by superscript two and subscript n: The sum of the square of values is the result you get
when each individual value is squared (that is, multiplied by itself) and all the squares are added
together.
8.5 Memory Operations.
There are 10 separate memories for storing conversion factors, partial results, etc. They are
numbered 0 to 9. The commands for memory number 1, for example, are as follows:
Clear memory 1: C 1;
Store number in memory 1: S 1;
Add to memory 1: A 1;
Recall contents of memory 1: R 1;