bc scale: How to avoid rounding? (Calculate small binomial probability)

5 votes

5 answers

6940 views

                          Following code calculates the Binomial Probability of a success event k out of n trials:
    
    n=144
    prob=$(echo "0.0139" | bc)

    echo -e "Enter no.:" 
    read passedno
    
    k=$passedno
    nCk2() {
        num=1
        den=1
        for((i = 1; i <= $2; ++i)); do
            ((num *= $1 + 1 - i)) && ((den *= i))
        done
        echo $((num / den))
    }
    
    binomcoef=$(nCk2 $n $k)
    
    binprobab=$(echo "scale=8; $binomcoef*($prob^$k)*((1-$prob)^($n-$k))" | bc)
    
    echo $binprobab

When for $passedno (=k) "5" is entered, then the result is shown as 0 (instead of "0.03566482") whereas with "4" passed I get ".07261898".


**How can I print the output with given precision of 8 decimal digits without getting the rounded value of the output?**

                        

Asked by Aliakbar Ahmadi (203 rep)

Jul 29, 2015, 10:58 AM
Last activity: Dec 15, 2019, 01:37 AM

bc scale: How to avoid rounding? (Calculate small binomial probability)

Related Questions