Scribepost for September 26, 2009

QUESTION #8:

The table shows the decibel levels of different sounds in the environment.


a) Use a bar graph to display the data. What is one advantage of using a bar graph?

An advantage of using a bar graph is, it’s an easy way to compare data and to make it even easier, the intervals are a big help too.

b) Could you use a line graph to display the data? Explain.

Yes, because a line graph is very similar to a bar graph except the bars are replaced by dots connected with lines.

c) Could you use a circle graph to display the data? Explain.

No, because the numbers go too high and there are too many categories.

d) Would a pictograph be an effective way to display the data? Explain why or why not.

No, because a pictograph is only used for one topic and how things change over time.

Celdrick's Scribepost for September

7. The table shows the heights of two friends
measured over time.


















a) Use a double bar graph and a double
line graph to display the data.
























b) How are the trends for Andrea and
Lewis similar? How are they different?

The trends are similar in that both friends’ heights are
increasing from age 2 to age 14. The trends are different
in that Andrea’s height stops increasing after age 14, but
Lewis’ height continues to increase after age 14.



c) Which graph do you think more clearly
shows each student’s height trend?
Explain your choice.

Because the data do not represent a comparison
of parts to a whole, a circle graph would not be a good
choice of graph.



d) Would two circle graphs be effective
for displaying the data? Explain why
or why not.

A pictograph could be used, but it
would not be as accurate as a bar graph because of the
fractions of pictures required to represent these data.

Scribepost for September 24, 2009

QUESTION #4

Ravi spends 10 more on food than on movies. I used the pictograph to check, because I can just count how much more or less they are from each other. But to be more specific, you could use the circle graph.

The circle graph shows this more clearly. Because if you look at the clothing and food, they are both 25%, which is half the money he spends.

You can easily calculate the number using the pictograph, but if you use the circle graph you have to find out wat the percentage is to the what the total is.

Misrepresenting Data Scribepost for Sept.27 2009, Binesi8-17

Misrepresenting Data

The Same	The Differences
The x-axis	y-axis
Increase in sales	Intervals
Title is the same	Axis break
Dots/information

Axis Break- a break in the y-axis that lets you jump from 1 number to another rather than a  continuous set of numbers.

 1. Explain how this graph could be misleading.

a) The axis break makes it look like gas prices decreased greatly. When it actually only decreased by 0.05 cents.

1. 2. What conclusion does the graph suggest about the price of gas at the end of the day compared with the price at the beginning of the day?

a) That gas prices made a big jump down in the evening from the morning.

2 3. Describe how to redraw the graph to represent the data more accurately.

b) When redrawing the graph, don’t use an axis break.

1. Explain how this graph could be misleading.

a) They made the pizza really big, so it looks like pizza is the most popular food.

2. What conclusion does the graph suggest about favourite lunch specials?

b) It’s suggesting that pizza is the most popular food, and that mac and cheese is second.

3. How could you redraw the graph to represent the data more accurately?

c) You could make every picture the same size.

Scribepost for September 23, 2009

Question #9:



The graphs show the categories of books that were signed out from a library over a year.










a) Estimate how many times more popular science fiction books are than history books.

The science fiction books are 24% more popular than the history books.


b) Which graph helped you answer part a)? Why did you choose this
graph?

The graph that I used to help me answer part a) was the the circle graph. I chose the circle graph because the percents are already there instead of using the bar graph. Because with bar graph, I still need to convert the numbers into percents and then do the subtracting.


c) Which category of books has approximately the same number of sign outs as history and sports books together? Show your thinking.

Mystery has the same number of sign outs as sports and history put together. I got that because if you add up all the sports books and history books you will get the same number of sign outs as the mystery books.


d) Which graph helped you answer part c)? Why did you choose this graph?

The graph that helped me answer part c) was the circle graph because you could easily see that the percent of history (10%) and the percent of sports (13%) are equal to the percent of mystery books (23%). I chose to use the circle graph because the percents were easier to work with than the bar graph because with the bar graph you will have a hard time trying to find the exact number because of how high the intervals are.


e) The library has $12 000 to spend on books based on their popularity. How much money should be spent for each category? Show your work.

History: $1 200
Sports: $ 1 560
Teen Romance: $ 2 400
Mystery: $ 2 760
Science Fiction: $ 4 080

I got those answers by using a ratio table, by finding 1% and then multiplying it by the other percents.




















f) Which graph did you use to answer part e)? Why did you choose this graph?

I used the circle graph to answer part e). I chose it because I found 1% and then just multiplied it by the other percents but if I used the bar graph I would have to work harder to get the same answer and do many more steps.

scribepost for September 15, 2009

QUESTION #5

The piano that Sara, Ann, and Min use is available for 40 h of practice every week. The graphs show how they divide the practice time.

a) What information does each graph provide?
The circle graph shows the percent for all three girls. The bar graph shows the number of hours the girls used the piano.

b) Write and answer one question about the data that can be answered from the circle graph.

Question: Who has the most hours of practice time? Answer: Ann has the most hours of practice time.

c) Write and answer one question about the data that can be answered from the bar graph.
Question: How many more hours does Ann have than Sara? Answer: Ann has 6 more hours of practice time than Sara.

Welcome to Blogging

A Colleague of mine Mr. Kuropatwa created this post for his students. Since it is Internet Safety Week please pay attention to the videos below.

Blogging is a very public activity. Anything that gets posted on the internet stays there. Forever. Deleting a post simply removes it from the blog it was posted to. Copies of the post may exist scattered all over the internet. I have come across posts from my students on blogs as far away as Sweden! That is why we are being so careful to respect your privacy and using first names only. We do not use pictures of ourselves. If you really want a graphic image associated with your posting use an avatar -- a picture of something that represents you but IS NOT of you.

Here are a few videos that illustrate some of what I want you to think about:




Two teachers in the U.S.A. worked with their classes to come up with a list of guidelines for student bloggers.

One of them, Bud Hunt, has these suggestions, among others:

1. Students using blogs are expected to treat blogspaces as classroom spaces. Speech that is inappropriate for class is not appropriate for our blog. While we encourage you to engage in debate and conversation with other bloggers, we also expect that you will conduct yourself in a manner reflective of a representative of this school.
2. Never EVER EVER give out or record personal information on our blog. Our blog exists as a public space on the Internet. Don’t share anything that you don’t want the world to know. For your safety, be careful what you say, too. Don’t give out your phone number or home address. This is particularly important to remember if you have a personal online journal or blog elsewhere.
3. Again, your blog is a public space. And if you put it on the Internet, odds are really good that it will stay on the Internet. Always. That means ten years from now when you are looking for a job, it might be possible for an employer to discover some really hateful and immature things you said when you were younger and more prone to foolish things. Be sure that anything you write you are proud of. It can come back to haunt you if you don’t.
4. Never link to something you haven’t read. While it isn’t your job to police the Internet, when you link to something, you should make sure it is something that you really want to be associated with. If a link contains material that might be creepy or make some people uncomfortable, you should probably try a different source.

Another teacher, Steve Lazar, developed a set of guidelines in consultation with his students. You can read them here.

Look over the guidelines and add the ones you like in the comments section below this post; either from one of Steve's students or one of your own. I think Bud's suggestions are excellent. We'll be using the one's I highlighted above as a basis for how we will use our blog.

Cheers,
Mr. K.

I could not have written it any better. Enjoy blogging and use your head. Thanks

Mr. Harbeck