Question

find the standard deviation of binomial random variable. A die is rolled 18 times and the number of fours that comes up is tallied

Answer 1

Complete Question

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Answer:

The standard deviation is  $\sigma =1.5811$

Step-by-step explanation:

  The  sample  size is  n  =  18

 

Generally the probability of getting a four in the toss of the fair die is mathematically represented as

          $p = \frac{1}{6 }$

While  the probability of not getting a four is  

          $q = 1 - p$

          $q = 1 - \frac{1}{6}$

           $q = \frac{5}{6}$

Now the standard deviation for the binomial random number is mathematically represented as

      $\sigma = \sqrt{n * pq }$

substituting  values  

     $\sigma = \sqrt{18 * \frac{1}{6}* \frac{5}{6} }$

      $\sigma =1.5811$