Question

Quiz 2 he average systolic x There is an upward tr X A study of the checkc x urses.ucf.edu/courses/1316000/quizzes/1847423/take DQuestion 1 1 pts A study of the checkout times of 100 customers at a supermarket resulted in the distribution below. Find the standard deviation of the distribution Checkout times (minutes) Frequency 0.5-1.5 1.5-2.5 2.5-3.5 3.5-4.5 4.5-5.5 15 20 15 20 30 122 146 157 2.13 Questin

Answer 1

$\begin{tabular}{lrrrrr} \hline Intervals & x & f & fx & xx & fxx \\ \hline 0.5 - 1.5 & 1 & 15 & 15 & 1 & 15 \\ 1.5 - 2.5 & 2 & 20 & 40 & 4 & 80 \\ 2.5 - 3.5 & 3 & 15 & 45 & 9 & 135 \\ 3.5 - 4.5 & 4 & 20 & 80 & 16 & 320 \\ 4.5 - 5.5 & 5 & 30 & 150 & 25 & 750 \\ \hline \end{tabular}$
Since we know that
$\\Mean(\bar{x}) = \frac{\sum fx}{n} = 3.3 \\Variance(\sigma^2) = \frac{\sum fx^2}{n} - \bar{x}^2 = \frac{1300.0}{100.0} - 3.3^2 = 2.11 \\Standard Deviation(\sigma) = \sqrt{Variance} = 1.4526 \approx 1.46$

Correct option is B
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