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Suicide rate

  1. Jul 7, 2010 #1
    Male and female suicide rates are out of total male population and total female population, respectively (i.e. total number of male suicides divided by total male population). The total rate of suicides is based on the total number of suicides divided by the total population rather than merely the average of the male and female suicide rates, because the gender ratio in most countries is not 1:1.

    Example:
    In 2008 Lithuania had suicide rates of 55.9 male, 9.1 female, 30.7 combined (male plus female). The suicide rate is per 100,000 people per year.

    Q1:
    That means in Lithuania almost 60 males out of 100,000 committed suicide. Am I correct?

    Q2:
    I don't understand the part in red.

    Let's say total population is 100 persons. In a certain year 10 males commit suicide, 5 females commit suicide, there are total 60 females and 40 males.

    Even if there were equal number, 1:1 ratio, of females and males (i.e. 50 females and 50 males) what difference would it make?

    What does average and gender ratio have to do with it?


    Please help me with the above questions. Thanks, in advance.
     
  2. jcsd
  3. Jul 7, 2010 #2

    Office_Shredder

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    Let's look at your example. If there are 60 females and 40 males, the male suicide rate is .25 suicides per person, and the female suicide rate is .08333 suicides per person. Naively, you might just add the two together and divide by two

    [tex]\frac{.25+.08333}{2}=.1667[/tex].

    But really there were 15 suicides out of 100 people, for a suicide rate of .15. The part in red says that it's calculating the actual suicide rate, which is the .15 here, rather than just averaging the male and female suicide rates
     
  4. Jul 7, 2010 #3

    arildno

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    Office Shredder has mainly answered this, but we can look at it another way:
    Let S be the total number of suicides, S_M and S_F the male&female suicides respectively, N the total population, with N_M and N_F readily defined.

    Let the gross total suicide rate be R, and R_M&R_F easily defined.

    Let P_M&P_F be the male and female population frequency, respectively.

    We then have:
    [tex]R=\frac{S}{N}=\frac{S_{M}}{N}+\frac{S_{F}}{N}=\frac{N_{M}}{N}*\frac{S_{M}}{N_{M}}+\frac{N_{F}}{N}*\frac{S_{F}}{N_{F}}=P_{M}*R_{M}+P_{F}*R_{F}[/tex]

    Note that IF we had:
    [tex]P_{M}=P_{F}=\frac{1}{2}[/tex], the R would be the arithmetic average of the sex-rates.

    It is not, it is the weighted average, the weights being the frequencies of the two genders.
     
  5. Jul 7, 2010 #4
    Hi Arild

    Did you mean to say suicide-rates? Please correct me if I'm wrong. Thanks.

     
  6. Jul 7, 2010 #5

    arildno

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    OOps, yes. That should be the suicide rates for each of the sexes, R_M and R_F. Sorry, my fault.
     
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