<< Chapter < Page Chapter >> Page >

Mathematics

Grade 9

Number patterns

Graphical representations

Equations statistics

Probability theory

Module 20

Understanding the context and vocabulary of probability

What is gambling all about?

ACTIVITY 1

To understand the context and vocabulary of probability

[LO 11.2, 5.1, 5.6]

1 The following very ordinary statements all deal with probability – but they are not all perfectly accurate. With your partner, study them and decide what is left unsaid, or what information you need to be able to evaluate them. Write down the results of your discussion.

For example : “The sun will come up tomorrow morning” really means: “If I go by the fact that the sun has come up every morning of my life, I am very certain that it will happen again tomorrow morning.”

1.1 If I toss a coin, there is a 50:50 chance that it will land tails up.

1.2 Kevin is certain to phone me tonight.

1.3 It is virtually impossible to win the lottery.

1.4 If you have a positive HIV test, then you will die of AIDS.

1.5 You are more likely to die of a spider-bite than of a lightning strike.

1.6 If you are told that every raffle ticket has two numbers, you have a double chance to win.

1.7 If you don’t play the Lotto, you are certain not to win.

1.8 In a room of 24 people, you are likely to find two people with the same birthday.

1.9 There is a 25% chance of rain tomorrow.

1.10 You are as likely to get a three as a four when you throw a die.

  • Check the quality of your answers:

2 Refer to the following scale

  • The likelihood of something happening must lie somewhere along this line of probabilities. Nothing can be less likely than 0%, and nothing can be more likely than 100%. If you throw an ordinary six-sided die, then it is certain (meaning 100% on the above scale) that the number it shows will be either 1, 2, 3, 4, 5 or 6. It is impossible (0%) that it will show a 7. We can’t always be sure exactly where a certain probability lies, but in some cases the probability can be worked out exactly.
  • Write down at which percentage of the scale above each of the following statements falls; afterwards discuss your answers with your partner.

2.1 I will throw a six with an ordinary die.

2.2 If you pick a Smartie with your eyes closed, it will be a red one.

2.3 I will visit a friend next weekend.

2.4 The numbers 1, 2, 3, 4, 5 and 6 are equally likely from throwing a die.

2.5 I will meet the president of South Africa someday.

2.6 I will stay the same height for the next year.

2.7 I will get a cold next winter.

2.8 I will be the president of South Africa someday.

  • How was the quality of my work now?
  • Here is the same scale with other values:

  • These same probabilities are often written as a simplified fraction. Note that the line goes from 0 (impossible) to 1 (certain). We can’t have probabilities that are greater than 1 – nothing can be more likely than absolutely certain! In other words, these probabilities can’t be fractions with a larger numerator than denominator.
  • Let’s look at the die again to make it clear how it works. The dice can show one of six numbers, but the chance that it will be a six is only one out of six chances. Look at it this way: if six friends throw one dice, and each chooses a different number from 1 to 6, then it is certain that one will be right! So, each of them has only 1 of the 6 chances to be right. The fraction (the probability) is 1 6 size 12{ { {1} over {6} } } {} , which lies between 10% and 20% on the scale.

Questions & Answers

can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
ninjadapaul
20/(×-6^2)
Salomon
okay, so you have 6 raised to the power of 2. what is that part of your answer
ninjadapaul
I don't understand what the A with approx sign and the boxed x mean
ninjadapaul
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
Salomon
I'm not sure why it wrote it the other way
Salomon
I got X =-6
Salomon
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
ninjadapaul
oops. ignore that.
ninjadapaul
so you not have an equal sign anywhere in the original equation?
ninjadapaul
Commplementary angles
Idrissa Reply
hello
Sherica
im all ears I need to learn
Sherica
right! what he said ⤴⤴⤴
Tamia
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Al
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
yes
Asali
I'm not good at math so would you help me
Samantha
what is the problem that i will help you to self with?
Asali
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
China
Cied
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
Porter
many many of nanotubes
Porter
what is the k.e before it land
Yasmin
what is the function of carbon nanotubes?
Cesar
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
AMJAD
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
AMJAD
what is system testing
AMJAD
what is the application of nanotechnology?
Stotaw
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Good
Got questions? Join the online conversation and get instant answers!
QuizOver.com Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Mathematics grade 9. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col11056/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Mathematics grade 9' conversation and receive update notifications?

Ask