3Thavo §8.4(A) and §10.4(B)

• Wiskunde
• Middelbare school
• vwo
• Leerjaar 3

Welcome to the 6th long distance math lesson!

Programme for today / Homework for Thursday:

Math A:  §8.4 Box plot        or

Math B:  §10.4 Median.

Math A §8.4 Box plot, first.

Math B pupils,

please stay on the LessonUp;

+ it might be interesting to see what Math it is your classmates

are going to do

+ in a few minutes we move over to Ch 10!

TASK:  Choose the correct statements in the next slide.

Remember the letter(s) of your choice!

A. The 2 boundaries (grenzen) of an interval notation tell you the class width.

B. Relative numbers are the actual ones; absolute numbers are percentages.

C. If the price goes up by 10 % you multiply the old price by 0.10 to get the                new one.

D. The upper quartile is between 25 % of the numbers and 75 % of 

     the numbers, from left to right.

Which one is correct?

1. class width
2. relative and absolute
3. percentages
4. upper quartile

Answer:

Only A was correct!

When you subtract the lowest boundary from the highest,

you get the class width.

Now follows §8.4's content:

A BOX PLOT !

• Watch this picture.
  
• It is an illustration of what you will learn and make today! 
• The numbers between Q1 and Q3 are 'plotted in the BOX',  so it is a   BOX PLOT!

Do you remember from §8.3 the MEASURES of SPREAD (spreiding)?

 Here is a Summary:

• The median is the number in the middle.
• Q1 = lower quartile   is the middle number of the first half
• Q3 = upper quartile  is the middle number of the second half.
• IQR = interquartile range  is   Q3 - Q1, so the length of the Box (new!)
• range = max - min 

Recap on §8.3, by an Example:

+   Suppose we have these 10 values:       2, 3, 4, 5, 5, 6, 7, 8, 9, 10

+ the median (middle one) is (5+6) : 2 = 5.5

+ the lower quartile = Q1 = median of first half = 4

+ the upper quartile = Q3 = median of second half = 8

+ interquartile range = Q3 - Q1 = 8 -4 = 4

+ range = 10 - 2 = 8 

The next slide ...

shows you precisely how to

• calculate : median, Q1 and Q3
• draw the BOX PLOT

Math A pupils: I wish you every succes,

doing §8.4.

Now it's high time for Mat B: §10.4 !

Math B:  §10.4 MEDIAN

Do you remember and understand the previous paragraphs?

A question about them follows!

You may consult book 3B, because you do not have to know all content by heart just now!

Which statement(s) is(are) correct?

They all concern triangles (Open your Book!).

A. Perpendicular Bisectors(PB), Altitudes(A) and 

     Angle Bisectors(AB) all go through one point.

B. Making PB-s and A-s is called 'constructing', for AB-s it's just 'drawing'.

C. Making PB-s and AB-s is 'constructing', A-s you draw.

D. The vital difference between drawing and constructing is that for the

     latter you also need a pair of compasses.

Fill in the good statement(s).

1. PB-s A-s and AB-s go through one point.
2. PB-s and A-s: constructing
3. PB-s and AB-s is constructing A-s is drawing
4. difference is pair of compasses

Constructing - drawing.

+ When making Perpendicular Bisectors and

Angle Bisectors:              

always use a pair of compasses!

+ Reason: then you get very precise results!

+ Exercise 18b and 18c should've asked you

to 'CONSTRUCT' and not 'plot' and 'draw'.

So sad, so very sad...              You may  change this with a pencil in your book! 

By the way,

your classmates also work on the Median, but then 

it is about Numbers!

Both mean 'something in the middle'!

Drawing the median can be done with geo and pencil only.

And what bout the 3 medians of a triangle?

After dealing with §10.1, §10.2 and §10.3 you might have

expected:

all 3 go through the same point:

the CENTROID.

This is a great paragraph:

It contains, among others, these tasks: 

+ plotting or drawing                        

+ explaining

+ calculating  

+ reasoning,     examples on next slides!

plotting or drawing:

explaining:

calculating:

Perform all these different tasks 

as good as you can!

Remark:

+   REASONING (redeneren), by logical steps,  is a skill that will            be asked from you in the higher forms more often!

+   It distinguishes (sets apart) Math B from Math A.

Homework time.

Math A: §8.4 

Math B: §10.4