Help with Observations

[EllieM]

Ok so for my science fair topic i am doing "how does exercise affect heart rate" basically i am taking the resting heart rate of 7th graders and then having them run on a treadmill for tem minutes, and then seeing how long it takes for their heart rate to return to resting, i tested my subjects three times each to see if running more would make it take less time for the heart rate to return to resting and then compared boys vs. girls. I made my graphs and found that i with every trial it took less time for the heart rate to return to resting and there was a bigger difference in each time with the girls heart rates. now i have to do a "brief write up of my observatons" what am i supposed to write? oh yeah and this is not my conclusion it is a write up of my observations...so what does it mean? thanks in advance!!!

[donnahardy2]

Hi Ellie,

This sounds like a very interesting project. Here are my suggestions for your results and observation section:

First, how did you graph your results? One way to do this would be to make a bar graph with showing the frequency of the time differences, with one graph for girls and another for boys. This should result in a bell-shaped curve if you have enough data points. Please let us know how you did your graph for this section.

Next, you need to make some calculations using your data so you can compare the differences between girls and boys. First, go to the science buddies project guide at the top of this page, and read the section on "data analysis and graphs," and then go to the related link and read about "variance and standard deviation."

First calculate the mean time difference for girls and boys separately. Then, calculate the standard deviation of the results. If you have Microsoft Excel on your computer, it has a function to calculate this after you enter all of your data, and that's the easiest way to calculate standard deviation. Are you good at math, or do you need some more help here?

In your observations section, you can state that the mean time difference and the standard deviation for girls and for boys. You can also add your observations about the trend in shorter times with repeated trials by saying that the time differences were shorter in subsequent trials "X" percentage of the time.

If you do this, then you will be set for the conclusion section of your write up. There are some other calculations you can do if you are interested in learning about them, but the easiest way to make your conclusion will be to compare the mean time differences between your two groups. If the difference is two standard deviations or greater, then your results are definitely significant. If the difference is less than two standard deviations, then your results are not conclusive, and you will then have lots to discuss in this section of the write up.

Please post again if you have any questions. Also, please post your data as it would be helpful for us to see what happened in your project.

Donna Hardy

[EllieM]

hmmm i an not exactly sure what you mean...i get the graph part but...

thanks for answering!!!!!!!!!!! her is my data /Users/christophermcgraw/Desktop/science fair graphs.xls

[donnahardy2]

Hi Ellie,

I can't open your results file. Can you just list the time differences for boys and for girls, including the individual values for each participant?

For the graph, on the X-axis mark the time differences, using minutes, from lowest to highest Make one bar for the mean (average of 3 readings) time difference for each participant. If two participants have the same time difference, then put two bars on that time slot.

Please tell me exactly what you don't understand. Do you need more information on making the graph, calculating the mean value, or calculating the standard deviation? Or everything?

Donna Hardy

[EllieM]

i have already made the graphs now i have to write about my observations (not a conclusion) and i dont understand what that means

[Courtney]

Hi Ellie,
If your teacher's instructions were "to write about your observations (not a conclusion)", then I suspect your teacher wants you to write in plan English some of the interesting things you notice about your data. Look at your graphs and think about them. What is surprising about the data you collected? What stands out right away when you look at your graphs? What is the difference between the slowest to recover and the fastest to recover? Compare and contrast the three trials. You already wrote down two things you noticed in your first post in this thread, "with every trial it took less time for the heart rate to return to resting and there was a bigger difference in each time with the girls heart rates." It might help to look at your printed graph and just have a conversation about it with someone in your family. The things you think of to tell your family member about your experiment are "observations" that you can write down for your teacher.

Ms. Hardy's reply gives you several other good ways of looking at your data and making observations. Ms. Hardy can help you even more if you ATTACH your graph. The link you posted before did NOT work. You need to use the UPLOAD ATTACHMENT tab that you will see below the box where you type your REPLY. While you are typing your next post, click UPLOAD ATTACHMENT and then browse to find your file. Click ADD THE FILE. Then click SUBMIT.

Sincerely,
Courtney
Science Buddies Staff Member

[EllieM]

heres my info...on here it is hard to read but on my xel it is reallygood ...soo yah

AVERAGES


BOYS GIRLS BOYS and GIRLS

1 2 3 4 5 Overall Avg 1 2 3 4 5 Overall Avg Overall Avg

RHR 79.67 83.33 82.33 76.50 75.00 79.37 RHR 75.00 85.67 93.33 88.00 90.50 86.50 82.93

5 Min 205.00 179.00 208.00 170.00 158.00 184.00 5 Min 168.00 169.33 175.67 118.00 171.00 160.40 172.20

10 Min 206.33 184.67 196.00 181.50 162.50 186.20 10 Min 167.00 176.67 177.33 141.50 172.50 167.00 176.60

Rec Time 7.99 7.52 6.91 7.36 4.57 6.87 Rec Time 6.01 9.60 5.05 2.06 6.25 5.79 6.33

[HeatherL]

Hi Ellie,

with every trial it took less time for the heart rate to return to resting

If I understand your description correctly, it looks like you saw a "training effect." When a person repeats the same exercise, the muscles learn to respond to that sort of exercise, and it doesn't have the same effect with repetition. In other words, it seems "easier" to do the same exercise again. This is an interesting observation, and is something you can definitely address in your discussion.

I put "effects of training on heart rate" into Google, and found an article about both exercise training and gender effects: http://europace.oxfordjournals.org/cgi/ ... act/9/1/55

I hope this helps you. Good luck!

Heather

[donnahardy2]

Hi Ellie,

Thanks for posting your data. I saw the summary on your other post, and I can't quite figure out which numbers you used to calculate the recovery time. What numbers for the girls gave you an average of 5.79 minutes? And, which numbers for the boys gave you an average of 6.87 minutes?

One comment on your decimal points. Your heart rate per minute numbers should be rounded to the nearest whole digit, because that is the number that is significant. Also, I suggest that you round off the minutes to the nearest 0.1 of a minute. Your numbers are only accurate to the nearest whole heart beat, and to the nearest 0.1 of a minute, so you should a decimal point that reflects the accuracy of the results. Here's a website that explains significant numbers.

http://www.shodor.org/UNChem/math/science/index.html

The next step is to determine if there is a significant difference in your results, and you can do this by using Excel to calculate the standard deviation. If you have your data in a column, click on the cell below one set of data (for example, the average recovery time for the girls), and under the "insert" tab, select function, and then select "STDEV." Then click OK, and you will have the standard deviation. Try this and see if your Excel program will do this. Next, either let me know about your data (1,2,3,4,5 (girls) 1,2,3,4,5 (boys), or post the standard deviations for your two sets of data. Comparing the standard deviations of the two sets of data will allow you compare

Also, in addition to the recovery time data, you have a lot more data that you could present in your project. You collected data over the entire experiment, so you could graph time on the x-axis, and heart rate/minute on the Y-axis, graphing the average of the 3 values for each subject, and using a different color for girls and boys. And, since you observed a trend in shorter times with subsequent trials, you could present the data of the individual trials. It just depends on how much time you want to spend analyzing your data.

Donna Hardy