According to the "American Freshman", the number of hours that college freshmen spend studying each week is normally distributed with a mean of 7 hours and a standard deviation of 5.3 hours. Use the 68-95-99.7 Rule to find the percentage of college freshmen who study between 7 and 12.3 hours each week. Round to the nearest percent.

Question

jim_thompson5910 · Answer

Are you familiar with the 68-95-99.7 Rule?

amistre64 · Answer

i learned it as the "empirical" rule

jim_thompson5910 · Answer

Same here, but I like the name "68-95-99.7 Rule" since it provides the probabilities in the name itself

amistre64 · Answer

i spose if you learn it as the "68-95-99.7", then you are bound to remember the .... yeah :)

anonymous · Answer

i don't know it

jim_thompson5910 · Answer

The 68-95-99.7 Rule says that 

68% of the distribution is within 1 standard deviation of the mean

95% of the distribution is within 2 standard deviations of the mean

99.7% of the distribution is within 3 standard deviations of the mean

jim_thompson5910 · Answer

Sound familiar?