# Archive for May, 2019

## Combinatorics

Posted by ricardogm on 28th May 2019

Hi

1. Two possibilities for today:

a) Use this hour for the project.

b) Solve combinatorics problems, below.

Here you are:

Permutations and combinations

Same thing in spanish

Another

And some examples.

And a calculator

Factorial calculator.

Some simple problems to practice:

6. How many ways can you arrange the letters from the word CODES?
7. At Scrabble you have the letters XZJYPVK. How many 3 letter arrangements can be
8. At travelling sales man must visit 15 towns. In how many different ways can he plan his
journey?
9. How many numbers between 100 and 1000 use only odd digits, no digit being repeated?
10. In Mastermind a code is picked using 4 out of 6 colours. How many codes are possible, if
no colour can be used twice?
11. There are 14 horses in a race. In how many ways can the first 3 places be filled?
12. A class contains 25 pupils. In how many ways can prizes be awarded in Latin, French and
Mathematics, if no pupil can win more than one prize?
13. In how many ways can eight books be arranged along a shelf?
14. At Scrabble the letters QWYPKGDZXBM are left in the bag. In how many ways can you
draw out four of them?
15. You are given 12 points on a plane, no three of them being in a straight line. How many
triangles can be drawn using the points as vertices?
16.You are given 9 points on a circle. How many chords do they form?
17. You have 10 blue flowers are 5 b red flowers. In how many ways can they be planted in a
row, if we do not distinguish between flowers of the same colour?
18. The travelling salesman of Question 8 decides to visit only 5 towns. In how many ways
can his selection be made? How many possible journeys does he have now?
19. In Bridge each player receives 13 out of the 52 cards. How many possible Bridge hands
are there?
20. A coin is tossed 10 times, and heads comes up 4 times. In how many ways can this have
happened?
21. You win a tennis set 6-4. How many ways can this have happened?

Posted in 4º ESO | No Comments »

## Two variables statistics theory

Posted by ricardogm on 21st May 2019

Hi

1. Today we are going to practice a little bit with geogebra and Powerpoint, hoping that it will be useful for your projects. Pay attention

a) These are the exercises we are going to work out with Geogebra: some exercises.

b) This is a real example of the statistics project:

c) I repeat here the structure of the project. It will be a Word document, or Powerpoint,  with, at least, these parts:

1. Frontpage with your names and the title of the project.

2. Introduction (in another page). Explaining the goal of the project, what you want to know, how you got the data, etc.

3. Another page with the data, in table form.

4. Another page with graphics.

5. One more with all the calculations.

6. And one with the final conclusions.

d) Remember, we are going to study the relationship between two variables, posibly with a survey. You need at least 30 data points. Less than that, it’s anecdotal.

2. The theory is here:

Here you are.

3. And some guide to interpret the values of r:

(Extract from Malawi Medical Journal:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3576830/)

Posted in 4º ESO | No Comments »

## Two dimensional statistics

Posted by ricardogm on 20th May 2019

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## Statistic project

Posted by ricardogm on 17th May 2019

1. First of all, we are going to organize the teams for the statistic project. Tell me the members of each team and a name for it.

2. Now a little information about the project. It will be a Word document, or Powerpoint,  with, at least, this structure:

1. Frontpage with your names and the title of the project.

2. Introduction (in another page). Explaining the goal of the project, what you want to know, how you got the data, etc.

3. Another page with the data, in table form.

4. Another page with graphics.

5. One more with all the calculations.

6. And one with the final conclusions.

3. Remember, we are going to study the relationship between two variables, posibly with a survey. You need al least 30 data points. Less than that, it’s anecdotal.

4. And we are going to learn to use geogebra in statistics, today with one variable, next friday with two. Pay attention

Ex.1 isolated data:

The number of occupants in passing cars are counted. The results are:

1 2 1 4 3 1 2 1 5 4
1 1 1 2 1 3 1 4 1 1
1 2 1 1 1 2 1 1 4 2
2 2 1 2 1 3 2 1 2 1

Ex. 2

A class of 40 students took a mock exam in maths. They were given percentage marks as follows:

73, 45, 62, 34, 59, 20, 48, 50, 78, 38, 52, 91, 57, 82, 46, 51, 62, 58, 39, 50, 72, 73, 63, 52, 41, 37, 28, 46, 71, 75, 36, 28, 44, 90, 51, 28, 60, 18, 47, 40.

As a bonus, this image links to some examples of terrible powerpoint design:

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## Perpendicular común a rectas que se cruzan

Posted by ricardogm on 1st May 2019

Muy buenas

Y un par de videos sobre el tema (usan el método que prefiero):

Posted in 2º Bach. CT | No Comments »