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phy 201
Your 'timer program' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** TIMER program_labelMessages **
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1 hour
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Operating the TIMER program
It is easy to operate the Timer program. All you have to do is click on the button labeled Click to Time Event.
Click that button about 10 times and describe what you see.
I see that there are three columns: The first one is the event time, middle is the clock time, and the last is the time interval.
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Now click on Initialize Counter, which will clear all the data from the timer window. Click the mouse as fast as you can until the TIMER window fills up. Be sure you get at least 20 time intervals.
If you miss a click, try again. Keep trying until you get at least 20 intervals without a missed or delayed click.
Copy your data starting in the next line:
1 2.122 2.122
2 2.286 0.164
3 2.454 0.168
4 2.64 0.186
5 2.801 0.161
6 2.968 0.167
7 3.138 0.17
8 3.306 0.168
9 3.466 0.16
10 3.65 0.184
11 3.828 0.178
12 3.988 0.16
13 4.172 0.184
14 4.348 0.176
15 4.535 0.183
16 4.711 0.176
17 4.894 0.172
18 5.07 0.175
19 5.242 0.17
20 5.417 0.231
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You got at least 20 time intervals. Based on your data what was the average of the first 20 time intervals? Note that you could get this average by averaging the first 20 intervals. My first few intervals were .15625, .15625, .1875, .171875, etc; I could just add up the first 20 intervals and divide by 20 to get the average. However there is an easier and quicker way to get the result, so use the easier way if you can.
Give your result, number only, in the first line, and starting in the second line explain how you got it.
0.2644
I copied the time interval column into numbers and then used the average function button to get the answer.
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One problem with using buttons to do your calculations is that we tend not to think about the calculation or apply common sense to the result.
The first thing you should do with data is think about what it means, observe trends and make estimates. In this case an estimate of the mean would be in order. Just by looking at the numbers you can see that the mean will be less than .2 seconds, since all the quick-click intervals but the last are less than .2 seconds, and the last isn't much more than .2 seconds.
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The longest interval you observed was .231 seconds. The mean cannot be .264 seconds.
You might have included that 2.12 second interval at the beginning when you found the average, but that is clearly not a quick-click interval and should not be included.
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There is, incidentally, another useful and important way to find the mean which is more efficient than adding the intervals and dividing.
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When I did this activity the first few lines of my data were as follows:
event number clock time time interval
1 11.67188 11.67188
2 11.875 0.203125
3 12.0625 0.1875
4 12.20313 0.140625
5 12.375 0.171875
6 12.54688 0.171875
7 12.73438 0.1875
8 12.92188 0.1875
9 13.10938 0.1875
10 13.28125 0.171875
11 13.4375 0.15625It looks like the same intervals keep popping up. For example .1875 seconds occurs 5 times out of the first 10 intervals, .171875 seconds occurs three times, and .203125 seconds, .140625 seconds and .15625 seconds each occur once.
A frequency distribution for my time intervals would be as follows:
time interval frequency
,140625 1
0.15625 1
0.171875 3
0.1875 5
0.203125 1What different time intervals did you observe in your first 20 intervals, and how many times did each occur? List below the different time intervals you observed and the number of times each occurred. List from the shortest to the longest interval, and use a comma between the time interval and its frequency. For example my data above would be listed at
.140625, 1
.1565, 1
.171875, 3
.1875, 5
.203125, 1
Your list should be in exactly this format, with no other symbols or characters.
2.122, 1
0.164, 1
0.168, 2
0.186, 1
0.161, 1
0.167, 1
0.17, 2
0.16, 2
0.184, 2
0.176, 3
0.187, 1
0.183, 1
0.172, 1
0.175, 1
0.231, 1
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You may make any comments or ask any question about the process so far in the box below
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On the 10 intervals I've shown you, do you really think I managed to get a time of .1875 seconds, accurate to 4 significant figures, on half of the intervals? If you do, I'm grateful for your confidence but I'm just not that good. No human being has that much neurological and muscular control.
So why do you think the TIMER program reported that time so frequently? Why weren't there times like .1830 seconds, or .1769 seconds? Does this mean that the TIMER program is flawed? Does that mean it's useless?
The TIMER is giving an approximation. It doesn’t have the capability to measure times that accurately. It has a flaw in that sense. No, it is not useless. It just gives approximations.
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Here are a few more lines of data, with an added column showing the difference between each time interval and the next.
clock time time interval difference from one time interval to next
9 13.10938 0.1875 -0.01563
10 13.28125 0.171875 -0.01563
11 13.4375 0.15625 0.03125
12 13.625 0.1875 -0.01563
13 13.79688 0.171875 0.015625
14 13.98438 0.1875 0.015625
15 14.1875 0.203125 -0.03125
16 14.35938 0.171875 -0.01563
17 14.51563 0.15625 0.03125Take a good look at that last column and tell us what you see in those numbers, and what this tells you about the TIMER program
That if you take the absolute zero of the time intervals that the differences are almost constant. There are negative numbers present so that is why I took the absolute zero. The numbers are very similar when you click fast, because you are clicking at a fairly regular constant speed.
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Now initialize the TIMER once more, and take a series of 10 relaxed breaths. Every time you start to inhale, hit the TIMER button.
My results for the first 7 complete breaths are as follows:
series of relaxed breaths
event number clock time time interval difference between time interval and next
1 1569.734 1569.734
2 1582.75 13.01563 0.32812
3 1596.094 13.34375 3.90625
4 1613.344 17.25 2.70313
5 1633.297 19.95313 1.35937
6 1654.609 21.3125 4.23438
7 1680.156 25.54688 2.15625
8 1707.859 27.70313 I didn't go on because the time between my breaths kept increasing, and I was afraid if I relaxed any more I might stop breathing altogether. It's going to take either more statistical analysis to determine whether that's a real danger, or a little common sense.
Report your results by just entering your time intervals, one to each line, in the box below. If I was entering my results I would enter
13.01563
13.34375
17.25
19.95313
21.3125
etc.
Enter your results in the same format:
3.68
6.736
10.1
13.513
16.715
19.449
22.275
25.089
27.979
30.269
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If you have any comments please insert them here
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Most likely you did not observe the same exact time interval twice, and if you did it did not happen nearly as often as when you did the fact clicks.
Why do you think this is exactly what we would expect?
Before, I was hitting the time button pretty consistently. However, breathing is irregular and the time interval between breaths shows this.
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Which of the following statements do you think is the most accurate?
a. The TIMER program is capable of determining the time between two events accurately to within about .1 second.
b. The TIMER program is capable of determining the time between two events accurately to within about .01 second.
c. The TIMER program is capable of determining the time between two events accurately to within about .001 second.
d. The TIMER program is capable of determining the time between two events accurately to within about .0001 second.
Enter your answer and your reasoning below:
I believe it is b.-to the .01 second. There are some intervals that have only two values after the decimal point.
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&#This lab submittion looks good. See my notes. Let me know if you have any questions.
Revision isn't requested, but if you do choose to submit revisions, clarifications or questions, please insert them into a copy of this document, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
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