Extra Practice Sample Answers

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Extra Practice Sample Answers

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Extra Practice 1 – Master 7.17

Lesson 7.1

1.a)Twenty students chose the trumpet; more students chose the saxophone than the clarinet.

b)20% of students chose the trumpet; the clarinet was the least popular choice.

c)Advantages: The bar graph lets you compare the popularity of instruments by the heights of the bars; you can find the number of students who chose each instrument by reading the height of the bar.
Disadvantages: It might be hard to determine the number of students who chose each instrument when the bar does not end on a grid line; the bar graph does not show you the percent of students who chose each instrument.

d)Advantages: The circle graph displays the percent of studentsin the class who chose each instrument; you can compare the popularity of different choicesusing the size of the sectors.
Disadvantages: The circle graph does not display the number of students who chose each instrument or how many students are in the class.

e)Line graphs are good for graphing data that change over time. Because thecategories represent instruments, not time, a line graph would not make sense.

2.a)The data change over time, so a line graph is best.

b)You could also use a bar graph or a pictograph.

c)No. There is no obvious part-to-whole relationship.

Extra Practice 2 – Master 7.18

Lesson 7.2

1.a)The graphs give the impression that it costs more to buy water from H2O water company than from Mountain Clear water company. They also seem to show that the cost of the water from H2O water company is increasing more rapidly than for Mountain Clear water company. However, the cost of a 25-L bottle of water from H2O water company in 2003 was about $38, but only about $30 from the Mountain Clear water company. Also, from 2003 to 2007, the cost of a bottle of water increased by about $10 for H2Owater company,andby about $7 forMountain Clear water company.

b)The graph of Mountain Clear water company’s costs has a vertical scale of 1 square represents $25, and the scale continues far beyond the greatest data value so the cost each year appears at the bottom of the graph. The graph of H2O water company’s costs has a vertical scale of
1 square represents $2, and the scale ends just above the greatest data value, so the most of the data appears in the top half of the graph.

c)The graph of Mountain Clear water company’s costs has a vertical scale of 1 square represents $25, and the scale continues far beyond the greatest data value so the trend lines have a very small slope. The vertical scale on the graph of H2O water company’s costs starts at $25 and ends at $40, so the difference between the data values for each year is exaggerated and the trend lines have steeper slopes.

d)Mountain Clear water company most likely made the graphs since they seem to show that the Mountain Clear water is cheaper and its costs are rising less rapidly than for H2Owater company.

2.a)

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Extra Practice Sample Answers continued

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Extra Practice 3 – Master 7.19

Lesson 7.3

1.× =

2.× =

3.a)i) × =

ii) ×= × =

iii) ×= × = =

P(red and a 4) = ;
P(blue and even) = =;
P(not yellow and odd) = =

4.a)×= =

b)× =

c)×= × =

d)0

Extra Practice 4 – Master 7.20

Lesson 7.4

1.a) × ×=

b) × ×= × × =

c) × ×= × × =

2.a)0.8 ×0.2 ×0.8 = 0.128 or 12.8%

b)0.8 ×0.8 ×0.8 = 0.512 or 51.2%

c)0.2 ×0.2 ×0.2 = 0.008 or 0.8%

d)0.2 ×0.2 ×0.8 = 0.032 or 3.2%

3.a) × ××=

b) ××=

4.a)× ××=

b)× ×× =

c)× ×× =

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