CENTRAL TENDENCY IN MATH- noelia 7-iv

MEASURES OF CENTRAL TENDENCY

 

What are the measures of central tendency?
A measure of central tendency is a measure that tells us where the middle of a bunch of data lies.The three most common measures of central tendency are the mean, the median, and the mode. 

WHAT IS THE MEAN: 
 Mean is the most common measure of central tendency. It is simply the sum of the numbers divided by the number of numbers in a set of data. This is also known as average.

WHAT IS THE MEDIAN: 
 Median is the number present in the middle when the numbers in a set of data are arranged in ascending or descending order. If the number of numbers in a data set is even, then the median is the mean of the two middle numbers.

WHAT IS THE MODE:
 Mode is the value that occurs most frequently in a set of data. 

EXAMPLES OF CENTRAL TENDENCY:
For the data 1, 2, 3, 4, 5, 5, 6, 7, 8 the measures of central tendency are 

Mean = 1+2+3+4+5+6+7+8      41
          -------------------------- = ----- = 4.56
                        9                     9

Median = 5


Mode = 5

26/11/13

Divisibility Rules

Divisibility by 2

Look at the last digit of the number, is it 0, 2, 4, 6, 0r 8 ?

If it is means that the number can be divisible by 2. 

EXAMPLE:

456 ---> it IS a multiple of 2 because the last number ( i mean 6)  is even.

25 ----. it is NOT divisible by 2 because the last number is IS NOT EVEN.

Divisibility by 3

A number can be divisible by 3 if the sum of all the digits of the number is multiple of 3.

 EXAMPLE:

 2079 -----> it IS divisible by 3, because if you add all the numbers it gives        you a multiple of 3.

  2+0+7+9 =18 ---> 18 is a multiple of 3.

  928 ------> it is NOT divisible by 3, because if you add all the digits the result is not a multiple of 3.

 

Divisibility by 4

A number is divisible by 4, if the last 2 digits of the number are multiple of 4.

                        

EXAMPLE:

4624 ------> it IS divisible by 4, because when you look at the last two numbers (24) you notice that it is a multiple of 4.

Divisibility by 5

Numbers ending in a 5 or a 0 are always divisible by 5.

EXAMPLE:

25, 50, 100, 5675 -------> they ARE divisible by 5 because they all end in 0 or 5.

Divisibility by 6

If the Number is divisible by 2 and 3 it is divisible by 6 also. Be careful! it is not one or the other. The number must be divisible by both 2 and 3 before you can conclude that it is divisible by 6.

EXAMPLE:

6294 -------> this number is divisible by 2, because it ends with an even number, and it is divisible by 3 because if you add them up it gives you 21. So, it IS divisible by 6.

Divisibility by 9

the rule is almostthe same as the rule for divisibility by 3. A number can be divisible by 9 if the sum of the digits are a multiple of 9.

EXAMPLE:

46926 -------> 4+6+9+2+6= 27------> 27 IS a multiple of 9. So, it IS divisible by 9.

Angles

Tipes of angles.

 <-------- obtuse angle

1. obtuse angle: is an angle bigger than a 90 degree angle. 

2. Right angle: is an angle o more bigger or smaller than 90 degrees.

         

3. Acute angle: are angles smaller than a 90 degree angle.

   

Basic Geometry Concepts

Points: In geometry ,we usually the point with a number or letter. Every point needs a name. To name a point, we can use a single letter.      

                      

Lines: We can use a line to connect two points on a sheet of paper. In geometry, a line is perfectly straight and extends forever in both directions.                                                                                                                                                                                                                                                           

Planes: A plane is made up of an infinite amount of lines. Two-dimensional figures are called plane figures.                                                                                                                                                                                                                                                   

Space: Space is the set of all points in the three dimensions. It is made up of an infinite number of planes. Figures in space are called solids.                                                                                                                                                                                                                            

Rays: A ray is part of a line that extends without end in one direction. It starts from one endpoint and extends forever in one direction.                                                                               

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mi primera semana de clases fue muy divertida porque conoci muchos profesores que nunca habia visto. tambien fue dificil porque en 6to yo estaba en regular y pase a avanzado y no es lo mismo. aunque con el tiempo uno se acostumbra a las tareas y tiene su horario para hacerlas tranquilamente sin estres.

mi primera semana del colegio tuvo muchas sorpresas, tanto sobre los temas de las materias, como de los nuevos profesores.