Question 750182
range = highest value - lowest value = 384 - 0 = 384 hr

variance
= (sum of squares of data values subtracted from the mean)/(number of data values - 1)
= 11108

standard deviation
= sqrt(variance)
= 105.4 hr

for reference: mean = (sum of all data values)/(number of data values) = 218.5 hr