6.) SAT Practice:
1 answer:
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Answer:
A) 90.32%
B) 90.11%
C) 81.546 miles per hour
D)77.93%
Step-by-step explanation:
Given data:
speed = 73.7 miles/hour
standard deviation = 4.77 miles /hour
a)
= P (z< 1.31)
= 0.90320 = 90.32%
b)
= P (-2.872< z< 1.31)
= P (z<1.31) - P(z<-2.87)
= 0.90320 - 0.00205
= 0.90115 = 90.11%
c) P(X <X) = 0.95
z = 1.645
x = 81.546 miles per hour
= P (z> -0.775)
= 0. 0.7793 = 77.93%