Question

The mean length of Beethoven’s nine symphonies is 37 minutes; the standard deviation is 12 minutes..
All of the following data values lie within how many standard deviations of the mean?
27 min, 30 min, 47 min, 35 min, 30 min, 40 min, 35 min, 22 min, 65 min


a.
1 standard deviation
c.
3 standard deviations
b.
2 standard deviations
d.
4 standard deviations

Answer 1

To find one standard deviation from the mean, you would add 12 to 37 and subtract 12 from 37 to get that the lengths should be between 25 and 49


But 22 minutes is outside of that range, so you have to go at least one more standard deviation in each direction (and see if there are any that are outside that range).