© 2004  Rasmus ehf

Statistics

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Lesson 1.

Freqency graphs - Bar graphs - Line graphs

Ten teenagers were asked how many times they went to the cinema  the last month. 

Name Number of cinema visits
Carl 1
Ann 0
John 0
Henry 2
Lila 1
Sharon 2
Grethe 1
Rebekke 4
Paul 0
Charles 1

The resuts are written in a frequency table that shows us how many of the ten teenagers went to the cinema once, twice, more often, or not at all.

Number of cinema visits Frequency (individuals)
0 3 Three teenagers did not go to the cinema during the month.
1 4 Four teenagers went once to the cinema during the month.
2 2 Two teenagers went twice to the cinema during the month.
3 0 No one went three times to the cinema during the month. 
4 1 One teenager went four times to the cinema during the month. 

Frequency means how often an event occurs. In statistics we would say that the event, "going to the cinema once a month", would have a frequency of 4.

What would the frequency be for "going to the cinema four times a month"? 

Answer: The frequency would be 1.

 

Bar graphs make it easier to find and understand statistical information. 

The results  above are shown in this bar graph. 

Number of cinema visits during the month   

Line graphs

Anna went  to Spain for a 7 day vacation. She measured the air temperature every day at 4 p.m.    Here are the results of her measurements.

Here the results are shown in a line graph.

Anna's Measurements

Day nr. Temp. in °C
1 20
2 25
3 25
4 30
5 15
6 25
7 35
The seventh day was the hottest with a temperature of 35°C.  The fifth day was the coolest with a temperature of 15°C.

Do It Yourself: Do a weather survey of your own by measuring the air temperature every day at the same time. Set up the results in a line graph as shown above. You can use the computer program Excel to help you.

Practice these methods and then try Quiz 1 on Statistics.
P.S. Remember to fill in your Check list as you go through the exercises and quizzes.