Adult IQ scores have a bell-shaped distribution with a mean of 100 and a standard deviation of 15. Use the Empirical Rule to find the percentage of adults with scores between 55 and 145.

Question

amistre64 · Answer

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amistre64 · Answer

the emirical rule simply states that:

68% of the data is within +-1 sd of the mean, 
95% is within +-2sd of the mean, and 
99% falls within +- 3 sd of the means

anonymous · Answer

ah the old bell curve. i even read that book

amistre64 · Answer

lets see how far 55 is away fromthe mean using 15 as a unit of measure.

100-55 = 45

45/15 = 3, 55 is 3 sds away or 99/2 since its only the left side

and 145 is 45 from the mean in the other direction; or 3 to the right

amistre64 · Answer

since 99% of the data falls within +-3 sds from the mean id says its:  99% :)

zarkon · Answer

Usually 99.7% is used for 3-sd about the mean.