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Grade 9

Number patterns, graphs, equations,

Statistics and probability

Module 18

Analyse data for meaningful patterns and measures


To analyse data for meaningful patterns and measures

[LO 5.3]

  • Now we need to gather information about the heights of the learners in your class. Fasten a measuring tape like the one dressmakers use to the side of the door, so that it is perfectly vertical. If you can’t find a tape, you can use some other way – maybe making small marks very accurately every centimetre on the wall, using rulers.
  • Each learner takes off her shoes and stands with her heels and back tightly against the wall. Someone who is tall enough holds a ruler or piece of cardboard flat on her head to see exactly how tall she is. It is a good idea to take the measurement in centimetres and not in millimetres. Write the answer on her hand (or on a piece of paper).
  • We do our first calculation in an interesting way: When everyone has been measured, all the pupils stand in line in the order of their heights.
  • From this line of pupils we get the first measurement of the average of the class. Write down the height of the pupil who is exactly in the centre of the line (equally far from the beginning as from the end). This number is called the median . There are as many learners shorter than she is, as there are taller than she is. Note: if there are an even number of learners in the class, then of course there will not be a middle person. In that case we take the two middle persons, add their heights and divide the answer by two.
  • Write down the median height for your class. If you are in a class with both boys and girls, work out the medians for the boys and girls separately
  • Next make a frequency table for the heights and use tallies to count how many of each height you have in the class.

Go back to the table of ages of siblings and find the median age of the boys and girls separately. Your table is likely to be very big, but here is a smaller example of what you should do:

  • See whether you agree that the median height for this group is 162 cm.
  • If you study the numbers in the last row (they give the frequencies of the different heights) you will see that 164 cm is the height that occurs most often as there are six learners who are 164 cm tall. This number is called the mode . We can think of it as the most popular height.
  • The ne x t calculation is the one that gives us the value that we usually call the average . Its proper name is the arithmetic mean , or just mean . You may already know how to calculate it: you add all the values and then divide the answer by the number of values. For the table above you divide 6156 by 38 to get a mean height for the class of 162 cm.
  • .We can make a table of these values:Use the table of ages of siblings again and calculate the mode and mean for boys and girls separately and then fill these values in on a table like the one alongside
Median 162 cm
Mode 164 cm
Mean 162 cm
  • These values (mode, median and mean) are together called measures of central tendency . They are all different kinds of averages . That is why, when we use the word average to refer to the arithmetic mean, we are not being perfectly accurate. From now on, you can use the word mean where you would have said average before.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
yes that's correct
I think
Nasa has use it in the 60's, copper as water purification in the moon travel.
nanocopper obvius
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
analytical skills graphene is prepared to kill any type viruses .
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Mathematics grade 9. OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col11056/1.1
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