SOLUTION: The number of adults sleep per night is normally distributed with a mean of 6.8 hours. assume that the standard deviation is unknown.
If 65% of adults sleep more than 6.2 hr/nig
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-> SOLUTION: The number of adults sleep per night is normally distributed with a mean of 6.8 hours. assume that the standard deviation is unknown.
If 65% of adults sleep more than 6.2 hr/nig
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Question 1135449: The number of adults sleep per night is normally distributed with a mean of 6.8 hours. assume that the standard deviation is unknown.
If 65% of adults sleep more than 6.2 hr/night. what is the variance? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! z>-0.385 for 65% being more than that value
z=(x-mean)/sd
-0.385=(6.2-6.8)/sd
-0.385 s=-0.6
s=+1.56
variance is s^2=2.43 hr^2 (rounding at end)
