The time required for a citizen to complete the 2010 u. s. census "long" form is normally distributed with a mean of 40 minutes and a standard deviation of 10 minutes. what is the third quartile (in minutes) for the time required to complete the form? 44.75 46.75 47.50 52.50

Question

Brittany Douglas

Mathematics

9 August, 23:17

The time required for a citizen to complete the 2010 u. s. census "long" form is normally distributed with a mean of 40 minutes and a standard deviation of 10 minutes. what is the third quartile (in minutes) for the time required to complete the form? 44.75 46.75 47.50 52.50

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Nakita · Answer 1

The third quartile will be evaluated as follows:

z-score = (x-mu) / sig

mu=40

sig=10

the z-value corresponding to 0.75 is 0.68

hence:

0.67 = (x-40) / 10

solving for x we get:

6.7=x-40

x=6.7+40

x=46.7

x~46.75