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Thread: Average Function.

  1. #1
    Member
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    Sharon Bracken
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    Feb 2001
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    13

    Default Average Function.

    When using the average function, how do you distinguish between a blank
    and zero in a numeric field?

    If test scores are 70, 80, 70, blank (student was absent and excused from taking test). Average desired = 73.3 not 55. Help.

  2. #2
    Alpha Software Employee Selwyn Rabins's Avatar
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    Selwyn Rabins
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    Boston, MA
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    Default RE: Average Function.

    you can't do it that simply because there is no difference in a5 between a "null" numeric value and 0.

    on the assumption that no one who actually takes the test got a 0, you could create a calc field:

    iif(sore=0,0,1)

    this calc field will be 0 if the score was 0 or null, and 1 otherwise.

    your average is then the sum of the scores divided by the sum of this calc field.

  3. #3
    "Certified" Alphaholic
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    William Hanigsberg
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    Default RE: Average Function.

    Sharon,

    Not to over dramatize, but I have lived with this problem.

    Selwyn suggest a way of working with the default behavior but I believe the variabilities of real life in the classroom are such that no default behavior will suit you. You will have to force the averaging to behave the way the individual case requires.

    There are several ways of doing this. I will suggest a couple.

    1. Twin fields: suppose your class has a midterm and a final exam and you are doing averages. For each exam have a character and a numeric field. You enter data into the character field and use field rules to calculate the numeric on the basis of the character field. Now you can put all kinds of stuff in the character field that a single numeric field wouldn't accept (e.g. ex[cused]) and your calc field rule can respond to these values which are usually termed "remarks". To keep them uniform and not confuse the calculation it is wise to allow remarks only from a drop down list which you control in field rules or form properties.

    2. Alternatively, you can have a logical field for each numeric and only include numerics where the logical field has the value of "true".


    Bill


  4. #4
    Bernard Posner
    Guest

    Default RE: Average Function.

    I've been extremely busy lately, and haven't had the opportunity to even look at V5 (although I have downloaded the latest patches)and probably won't be looking at it for another couple of weeks.

    However, I had a problem last year with the average function, and received help in solving it on this forum. So busy or not, I feel obligated to say something.

    I finally solved the problem (with help) by creating a field called "Pres/Abs/Exc" (you can call it anything you like)in which I recorded whether a student was present, absent or excused on a particular exam. If the student was absent or excused, the field in which grades were recorded was skipped, and therefore remained blank. If the student was present, a grade was recorded (in fact, an entry was required).

    I then had Alpha find a total of each students grades, and calculate a COUNT for the number of times they were "present". Since grades were only recorded when a student was present, the average became the TOTAL OF THE STUDENTS SCORES divided by THE COUNT OF THE TIMES THEY WERE PRESENT.

    Hope this was helpful.

  5. #5
    Member
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    James Urbanski
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    New Port Richey, FL
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    Default RE: Average Function.

    I have run into the same problem. My solution was to use a calculated field called counter which uses the isblank function. If the score field is blank the counter is 0 and if there is an entry the value is 1. I total the score fields and total the counter fieds and then divide the score total by the counter total. In a public high school that has a high transient rate, we often get kids in the middle of the term. Naturally, they can't be expected to take all the tests that they missed. We just pick them up where they are and try to factor transfer grades.

  6. #6
    Member
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    James Urbanski
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    New Port Richey, FL
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    Default RE: Average Function.

    You do know that you can set the display properties to sho whole numbers that automatically round up.

    Regards
    jim

  7. #7
    Member
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    Sharon Bracken
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    Feb 2001
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    Default RE: Average Function.

    I saw the light. Thanks for all your help and ideas.

    I am doing the twin fields, one character - Daily_Grade, one numeric - Numeric_Daily_Grade. The Numeric_Daily Grade has a calulating field rule of Val(Daily_Grade). Then I created another field, Count_Daily_Grade, that was numeric and stated if(Daily_Grade' ',1,0). I total all Numeric_Daily_Grade and divide by the Count_Daily_Grade and then grouped on student id because our instructors are entering these grades in their program areas with their students via network. Of course they will only see the average of 89.50%, or whatever, for their students that they have entered grades on, and we do have 0's. Works great, thanks. I love our networking on the forum. Now on to weighted grading. School's first day is very soon.

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