Basic Arithmetic

Primary mental abilities: groups of related skills organized into hypothetical constructs–Number- Word fluency–Verbal meaning- Inductive reasoning–Spatial orientation

Secondary mental abilities: clusters of related primary abilities used as a framework for describing intelligence’s structure; difficult to measure directly

Average: A calculated "central" value of a set of numbers (Also called the Arithmetic Mean.)

Mean, Median and Mode

The mean is the average of a data set.

The mode is the most common number in a data set.

The median is the middle of the set of numbers.

The mean (average) is found by adding all of the numbers together and dividing by the number of items in the set: 10 + 10 + 20 + 40 + 70 / 5 = 30.

The mode is the most common number in a set. For example, the mode in this set of numbers is 21

21, 21, 21, 23, 24, 26, 26, 28, 29, 30, 31, 33

The median is the middle number in a data set. To find the median, list your data points in ascending order and then find the middle number. The middle number in this set is 28 as there are 4 numbers below it and 4 numbers above:

23, 24, 26, 26, 28, 29, 30, 31, 33

Note: If you have an even set of numbers, average the middle two to find the mean. For example, the mean of this set of numbers is 28.5 (28 + 29 / 2).

23, 24, 26, 26, 28, 29, 30, 31, 33, 34

The range of a list a numbers and is just the difference between the largest and smallest values.

Chapter 2: Triangles 

Equilateral: "equal"-lateral (lateral means side) so they have all equal sides. An equilateral triangle has three equal lengths, and all the angles are equal which means they are each 60°.

Isosceles: An isosceles triangle has two lengths which are the same as each other, and two angles which are the same as each other.

Scalene: A scalene triangle has three different length sides, and three different angles.

Sum of the Interior Angles of a Triangle

The angles inside a triangle are called interior angles. The three interior angles in a triangle will always add up to 180°.

At each corner the exterior and interior angles are on a straight line, so at each corner these two angles add up to 180°.

Chapter 3: Sampling

Simple random sampling is a sampling technique where every item in the population has an even chance and likelihood of being selected in the sample. Here the selection of items completely depends on chance or by probability and therefore this sampling technique is also sometimes known as a method of chances.

"A simple random sample of size n consists of n individuals from the population chosen in such a way that every set of n individual has an equal chance to be the sample actually selected."