a tour of fundamental statistics

introducing

Basic Statistics

Simple as 1 2 3

Basic Definitions

1CentralTendencies

2Standard

Deviation

3Curves

Bell and Skewed

Centeral TendeciesMeanModeMedianRange

1

In statistics, the mean is the mathematical average of a set of numbers. The average is calculated by adding up two or more scores and dividing the total by the number of scores.

Example: 99, 97, 95, 93, 93, 93, 87, 85, 83, 62=887/10=88.7

Mean

In statistics, the median is the middle number in a given sequence of numbers, taken as the average of the two middle numbers when the sequence has an even number of numbers.

Example: 99, 97, 95, 93, 93, 93, 87, 85, 83, 62= 93

Median

In statistics, the mode is the number that appears most frequently.

Example: 99, 97, 95, 93, 93, 93, 87, 85, 83, 62= 93

the extent to which or the limits between which variation is possible:

Mode

In statistics, the range is the extent to which or the limits between which variation is possible:

Example: 99, 97, 95, 93, 93, 93, 87, 85, 83, 62= 99-62

Range

2 Standard Deviation

In statistics, the Standard Deviation is a measure of how spread out numbers are.

Example: 1.) 99, 97, 95, 93, 93, 93, 87, 85, 83, 62= sd 10.65051

2.) 99, 97, 95, 89, 84, 82, 76, 70, 66, 62= sd 12.53794

Standard Deviation

3 Curves

Normal and Skewed

Normal

• If this graph represents the example above, about 68% of the class scores are between 99 and 87.

• This represents the normal distribution curve.

Example: 99, 97, 95, 93, 93, 93, 87, 85, 83, 62= sd 10.65051

Skewed

99, 95, 84, 82, 80, 76, 72, 70, 66, 62= sd 12.53794

• This example represents a class with more scores on the lower side of the grading scale.

• Although the mean might be similar to the example of the class with normal distribution, the standard deviation shows that there are more lower scores with this class.

? But wait… There’s More!This is just a very basic overview of basic descriptive statistics.