f(x)=501,x∈[10,60]
(a) P(x<20)
P(x<20)=∫1020501dx
=50x∣1020
=5020−5010
=53
(b)P(x>55)
P(x>55)=∫5560501dx
=50x∣5560
=5060−5055
=101
=10%
(c) σ
σ=E(X2)−(E(x))2
E(x)=∫106050xdx
=100x2∣1060
=100602−102
=35
E(x2)=∫106050x2dx
=150x3∣1060
=150603−103
=34300
σ=34300−352
=14.434
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