Question

here are the shopping times (in minutes) for a sample of 5 shoppers at a particular computer store. 42, 39, 41, 35, 38 send data to calculator find the standard deviation of this sample of shopping times. round your answer to two decimal places. (if necessary, consult a list of formulas.)

Explanation:

Step1: Calculate the mean

The mean $\bar{x}=\frac{42 + 39+41+35+38}{5}=\frac{195}{5}=39$.

Step2: Calculate the squared - differences

$(42 - 39)^2=9$, $(39 - 39)^2 = 0$, $(41 - 39)^2=4$, $(35 - 39)^2 = 16$, $(38 - 39)^2=1$.

Step3: Calculate the variance

The sample variance $s^2=\frac{9 + 0+4+16+1}{5 - 1}=\frac{30}{4}=7.5$.

Step4: Calculate the standard deviation

The sample standard deviation $s=\sqrt{7.5}\approx2.74$.

Answer:

$2.74$