356,467 views
13 votes
13 votes
At a fast food restaurant, 51% of the customers order their food to go. In a sample of 300 customers, find the standard deviation of the number that order their food to go. (Round your answer to two places after the decimal point.)

User MRVDOG
by
3.3k points

1 Answer

14 votes
14 votes

The standard deviation of a number given a percentage is given as;


\begin{gathered} S\mathrm{}D=\sqrt[]{npq} \\ \text{Where n= sample size} \\ p=\text{ percentage of the customers that order their food to go } \\ q=\text{ percentage of the customers that do not order their food to go} \\ q=1-p \end{gathered}
\begin{gathered} SD=\sqrt[]{300(0.51)(0.49)} \\ SD=\sqrt[]{74.97} \\ SD=8.66 \end{gathered}

The standard deviation of the number that order their food to go is 8.66

User PeteLe
by
2.7k points