phy 121
If you included that data in your analysis, your results will be affected. If you look at the valid intervals, and your calculated mean, you will see that your mean doesn't lie 'in the middle' of your valid intervals. Often, in fact, this error leads to a mean interval length that is greater than any of the valid interval lengths.
As long as your calculations are otherwise correct, I'm not going to ask you to resubmit anything However you should make these comparisons yourself, and do submit a revision if you do have questions. To revise, simply insert your revisions, marking each insertion before and after with #### so I can easily identify it. &#
I took the total value from the 20th entry and then divided by 20. #$&* When I did this activity the first few lines of my data were as follows: event number clock time time interval 1 11.67188 11.67188 2 11.875 0.203125 3 12.0625 0.1875 4 12.20313 0.140625 5 12.375 0.171875 6 12.54688 0.171875 7 12.73438 0.1875 8 12.92188 0.1875 9 13.10938 0.1875 10 13.28125 0.171875 11 13.4375 0.15625 It looks like the same intervals keep popping up. For example .1875 seconds occurs 5 times out of the first 10 intervals, .171875 seconds occurs three times, and .203125 seconds, .140625 seconds and .15625 seconds each occur once. A frequency distribution for my time intervals would be as follows: time interval frequency ,140625 1 .15625 1 .171875 3 .1875 5 .203125 1 What different time intervals did you observe in your first 20 intervals, and how many times did each occur? List below the different time intervals you observed and the number of times each occurred. List from the shortest to the longest interval, and use a comma between the time interval and its frequency. For example my data above would be listed at .140625, 1 .1565, 1 .171875, 3 .1875, 5 .203125, 1 Your list should be in exactly this format, with no other symbols or characters. .12, 1 .121, 1 .13, 1 .132, 1 .134, 1 .135, 1 .138, 1 .14, 1 .143, 1 .144, 1 .145, 2 .146, 3 .151, 1 .159, 1 .241, 1 .267, 1 .438, 1 #$&* You may make any comments or ask any question about the process so far in the box below #$&* On the 10 intervals I've shown you, do you really think I managed to get a time of .1875 seconds, accurate to 4 significant figures, on half of the intervals? If you do, I'm grateful for your confidence but I'm just not that good. No human being has that much neurological and muscular control. So why do you think the TIMER program reported that time so frequently? Why weren't there times like .1830 seconds, or .1769 seconds? Does this mean that the TIMER program is flawed? Does that mean it's useless? The timer probably has select output values, one of which being .1875. The timer is not 100% accurate, but most likely will be for our purposes. #$&* 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 0.03125 Take 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 There are very few different values. The timer is set up as an aid to the student, not as an end-all timing program. #$&* Now initialize the TIMER once more, and take a series of 10 relaxed breaths. Every time you start to inhale, hit the TIMER button. My results for the first 7 complete breaths are as follows: series of relaxed breaths event number clock time time interval difference between time interval and next 1 1569.734 1569.734 2 1582.75 13.01563 0.32812 3 1596.094 13.34375 3.90625 4 1613.344 17.25 2.70313 5 1633.297 19.95313 1.35937 6 1654.609 21.3125 4.23438 7 1680.156 25.54688 2.15625 8 1707.859 27.70313 I didn't go on because the time between my breaths kept increasing, and I was afraid if I relaxed any more I might stop breathing altogether. It's going to take either more statistical analysis to determine whether that's a real danger, or a little common sense. Report your results by just entering your time intervals, one to each line, in the box below. If I was entering my results I would enter 13.01563 13.34375 17.25 19.95313 21.3125 etc. Enter your results in the same format: 4.819 5.32 5.093 4.853 4.881 4.965 5.382 6.042 4.565 5.702 4.969 #$&* If you have any comments please insert them here #$&* Most likely you did not observe the same exact time interval twice, and if you did it did not happen nearly as often as when you did the fact clicks. Why do you think this is exactly what we would expect? The output values are rounded to a decimal, and when breathing (something that spans several seconds instead of rapid clicks), it is much more difficult to get an identical answer. #$&* 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: C, as I had no 4 decimal answers. #$&* Note that the TIMER.exe program can save your data in a format that can be read by a spreadsheet (the TIMER applet cannot do so). This will be very handy in the future, so take a minute and do the following: 1. Click on the button at the lower right of the TIMER form, entitled Click to File Data. 2. A box will pop up allowing you to include an identifying message. You should generally choose to include such a message; for the data presently on your timer that might be 'series of regular breaths time at beginning of inhalation' or something similar. Type in whatever you think would serve as a good identifier for this data and OK that box. 3. A typical Save As window will appear. Decide where to save your data and what to call it, and proceed to save it. The program will save the file as a comma-delimited text file. 4. Open your spreadsheet program (typically Excel) and choose File > Open. Browse to the folder in which you just saved your data. Below the File Name line will be a File Type line; set this either to Text Files or All Files so your file will appear. Open it. 5. A series of windows will typically appear. In the first window make sure the file type chosen is Delimited, the proceed to the next window. 6. In the second window you will see a series of checkboxes; check the one entitled Comma, in order to select the comma-delimited file, then just click on Finish. Your data should appear in your spreadsheet, and can be manipulated as in any spreadsheet. Copy a few lines of the data from your spreadsheet below: Used online timer. #$&* Your instructor is trying to gauge the typical time spent by students on these experiments. Please answer the following question as accurately as you can, understanding that your answer will be used only for the stated purpose and has no bearing on your grades: Approximately how long did it take you to complete this experiment?