How are meandB and sddB derived for the functions in r?

[David Schutt]

I'm getting a different value when I use the meandB function in r than when I use the formula =10*LOG10(AVERAGE(10^(B**:B**/10))) to calculate the mean in Excel.

Thanks!

[Jérôme SUEUR]

Hello,

Just type in the R console the name of the function. This will return the code and so the math used.

HTH

Best
Jerome

> meandB

function (x, level = "IL") 

{

    if (level == "IL") {

        a <- 10

    }

    else {

        a <- 20

    }

    return(a * log10(mean(10^(x/a))))

}

> sddB

function (x, level = "IL") 

{

    if (level == "IL") {

        a <- 10

    }

    else {

        a <- 20

    }

    x <- 10^(x/a)

    res <- a * (sd(x)/(mean(x) * log(10)))

    return(res)

}

---

De: "David Schutt" <da...@penguinsinternational.org>
À: "seewave GROUP" <see...@googlegroups.com>
Envoyé: Vendredi 6 Octobre 2023 15:53:24
Objet: [seewave] How are meandB and sddB derived for the functions in r?

I'm getting a different value when I use the meandB function in r than when I use the formula =10*LOG10(AVERAGE(10^(B**:B**/10))) to calculate the mean in Excel.

Thanks!

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[David Schutt]

Great, thank you!