The time required to finish a test is normally distributed with a mean of 60 minutes and a standard deviation of 10 minutes. What is the probability that a student will finish the test between 50 and 60 minutes?

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Answer 1 · 2017-02-03T08:14:18

#0.3413#

#z=(x-u)/sigma#, where #u=60 and sigma =10#.

Therefore the probability student finish the test between 50 to 60 minutes is,

#P(50<=x<=60)=P((50-60)/10<=z<=(60-60)/10)#

#P(-1<=z<=0)=P(z<=0)-P(z<=-1)#

#=0.5000-0.1587=0.3413#