Week 16 B Lesson 1: Interpreting Graphs and Charts

Interpreting Graphs and Charts

Reading Charts

Bar Charts, Pictograms & Pie charts

Pictograms

• Uses picture icons

• Shows total for each person

Understanding :

• Mike makes a pictogram for the goals scored by players on the local football team.

  
  

• Tim scored 8 goals, Dwayne scored 12 goals, Mark scored 4 goals & Jay scored 8 goals.

  
  

• How could we make the pictogram easier to draw?

  
  

Understanding:

• Find the key - you need to know what the icon means.

• Look at the icon - what does half of the icon mean

Fill in the Blank

How many goals did Jess score?

(hover over the image to enlarge it)

Fill in the Blank

Who scored the most goals?

(hover over the image to enlarge it)

Fill in the Blank

How many more goals did max score more than Hannah?

(Hover over the image to enlarge it)

Fill in the Blank

How many goals did Greg score?

Fill in the Blank

how many goals did Dave score?

(Hover over the image to enlarge it)

Fill in the Blank

How many goals did Mo score?

(Hover over the image to enlarge it)

Fill in the Blank

How many goals did Todd score?

(Hover over the image to enlarge it)

Fill in the Blank

If each goal scored earns the team three points, how many points did the boys team get altogether?

(Hover over the image to enlarge it)

Bar Charts

Each category has a separate bar.

The height of the bar shows the total for each.

Multiple Choice

The shop sold 10 pairs of shoes.

(Hover over the image to enlarge it)

• True

• False

The shop sold 10 pairs of shoes

This is FALSE because

the bar reaches up to 8 on the frequency scale.

Multiple Choice

The shop sold three hats.

(Hover over the image to enalrge it)

• True

• False

The shop sold three hats.

This is TRUE because

the bar for hats reaches 3 on the frequency scale.

Multiple Choice

The shop sold 6 more T-shirts than hats.

(Hover over the image to enlarge it)

• True

• False

The shop sold 6 more T-shirts than hats

This is TRUE because

the number of hats is 3 and the number of t-shirts is 9.

3 + 6 = 9

Multiple Choice

The shop sold double the amount of shorts than hats.

(Hover over the image to enlarge it)

• True

• False

The shop sold double the number of shorts to hats.

This is FALSE because

there are 3 hats and there are 7 shorts.

Double 3 is 6 not 7.

Multiple Choice

In total the shop sold 25 items.

(Hover over the image to enlarge it)

• True

• False

The shop sold a total of 25 items.

This is FALSE because

Shoes = 8, T-shirts = 9, Hats = 3 and shorts = 7.

8 + 9 + 3 + 7 = 27 , not 25

Remember this?

A) 18 people in 6 sections

3 students per section.

Blue = 3

B) 40 people in 8 sections

5 students per section

Green = 15

C) 50 people in 10 sections

5 students per section

Yellow = 40

Remember this?

If the pie chart does not have equal sections you need to use 360 degrees as equal sections.

We can now think of the coloured section as a fraction of the circle.

Multiple Choice

What fraction of the pie chart is shaded?

(hover over the image to enlarge it)

Why is the correct answer ¹³⁵/₃₆₀ ?

• The coloured shape is 135 degrees.

• There is a total of 360 degrees

Now its a fractions question:

• calculate ¹³⁵/₃₆₀ of 400 students.

• ⁴⁰⁰ / ₃₆₀ x 135 = 150

• ¹³⁵ / ₃₆₀ x 400 = 150

Try these:

• how many people are in the shaded sections for each question?

How did you do?

• A) ⁶⁰/₃₆₀ is the fraction of the pie chart.

• ⁶⁰/₃₆₀ x 120 = 20

• D) ¹⁶⁰/₃₆₀ is the fraction of the pie chart.

• ¹⁶⁰/₃₆₀ x 180 = 80

Try these

how many people are in the shaded sections for each question?

Fill in the Blank

How many students are represented by the coloured section?

Answer 42

²¹⁰ / ₃₆₀ x 72

Fill in the Blank

How many people are represented in the coloured section?

Answer 495

⁸¹ / ₃₆₀ x 2200

Time Series Graphs

These are line graphs that give information over time.

This graph is about the temperature during th day.

Question 1

• What is the temperature at 1am?

• 9^oC

Question 2:

• Between what times is the temperature rising?

• The temperature is rising between 04:00 and 15:00.

Question 3:

• At what times is the temperature 18^oC ?

• The temperature is 18^oC at 13:00 and 16:00 - 17:00

Question 4:

• Use the graph to estimate the temperature at 16:30.

• at 16:30 the temperature is approximately 18^oC.

The plotted points:

• The table of information is a set of co-ordinates to be plotted.

• It is clear that (50,5) is an outlier because it doesn't seem to fit the pattern of points.

• Not including the outlier this means that the correlation is positive.

Why draw a line of best fit?

• A line of best fit gives us an idea of the "general pattern" of the points.

• The line of best fit is essential for estimating missing results

• If you are not directed to draw a line of best fit - draw one anyway!

Use your line of best fit to estimate:

• Khan plans a ride for 35 minutes, how far will he expect to go?

• Find 35 minutes, read to the line and then across to distance.

• Be ready to ESTIMATE from the scale. This example is approximately 17km.

Reliable Estimates?

Lite mobile recorded the price and sales of its phones and plotted a scatter diagram.

1) How many sales of £100 phones were there?

2) How many sales of £250 phones were there?

Reliable Estimates?

1) How many sales of £100 phones were there? 410

2) How many sales of £250 phones were there? 300

Which estimate is the most reliable?

Reliable Estimates?

Estimating for £100 IS reliable because it is INTERPOLATING within the data points we know.

Estimating for £200 IS NOT reliable because it is EXTRAPOLATING outside the data points we know.

Your teacher should have set you assignments on

Pie Charts

Scatter Diagrams