Hogwarts need to order more magic wands with a length of 20 cm. Since all magic wands are unique, the length varies normally with an average value of 19.7 cm and a standard deviation of 0.4 cm. What percentage of the wands are expected to be shorter than 19.3 cm?
+37084 Average (mean) = 19.7 cm ONE standad deviation (0.4) below the mean is 19.3 cm
How many wands are below one standard deviation?
from z-score table z = -1 equates to .1587 or 15.87%
