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Mathematics

Grade 9

Number patterns, graphs, equations,

Statistics and probability

Module 18

Analyse data for meaningful patterns and measures

ACTIVITY 1

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

what is microbiology
Agebe Reply
What is a cell
Odelana Reply
what is cell
Mohammed
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Nyibol Reply
what is microbiologist
Muhammad Reply
what is errata
Muhammad
is the branch of biology that deals with the study of microorganisms.
Ntefuni Reply
What is microbiology
Mercy Reply
studies of microbes
Louisiaste
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Ziyad Reply
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Muhamad Reply
Bacteria doesn't produce energy they are dependent upon their substrate in case of lack of nutrients they are able to make spores which helps them to sustain in harsh environments
_Adnan
But not all bacteria make spores, l mean Eukaryotic cells have Mitochondria which acts as powerhouse for them, since bacteria don't have it, what is the substitution for it?
Muhamad
they make spores
Louisiaste
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Aminu Reply
the significance of food webs for disease transmission
Abreham
food webs brings about an infection as an individual depends on number of diseased foods or carriers dully.
Mark
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Esinniobiwa Reply
Assimilatory nitrate reduction is a process that occurs in some microorganisms, such as bacteria and archaea, in which nitrate (NO3-) is reduced to nitrite (NO2-), and then further reduced to ammonia (NH3).
Elkana
This process is called assimilatory nitrate reduction because the nitrogen that is produced is incorporated in the cells of microorganisms where it can be used in the synthesis of amino acids and other nitrogen products
Elkana
Examples of thermophilic organisms
Shu Reply
Give Examples of thermophilic organisms
Shu
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Micheal Reply
Prevent foreign microbes to the host
Abubakar
they provide healthier benefits to their hosts
ayesha
They are friends to host only when Host immune system is strong and become enemies when the host immune system is weakened . very bad relationship!
Mark
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faisal Reply
cell is the smallest unit of life
Fauziya
cell is the smallest unit of life
Akanni
ok
Innocent
cell is the structural and functional unit of life
Hasan
is the fundamental units of Life
Musa
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Micheal Reply
There are nothing like emergency disease but there are some common medical emergency which can occur simultaneously like Bleeding,heart attack,Breathing difficulties,severe pain heart stock.Hope you will get my point .Have a nice day ❣️
_Adnan
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Innocent
I think infection prevention and control is the avoidance of all things we do that gives out break of infections and promotion of health practices that promote life
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_Adnan
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Adama
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ESTHER Reply
Many sites of the body have it Skin Nasal cavity Oral cavity Gastro intestinal tract
Safaa
skin
Asiina
skin,Oral,Nasal,GIt
Sadik
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all
Tesfaye
by fussion
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what are the ways of control and prevention of nosocomial infection in the hospital
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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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