Solve for x.. a) x= 8 B) x= 22.5 C) x= 32.4 D) x= 40.5
2 answers:
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Answer:
47.72% of the completion times is between 73.4 and 88.2 minutes
2.28% of the completion times is at most 58.6 minutes
Step-by-step explanation:
A reading test are normally distributed with a mean time of 73,4 minutes and a standard deviation of 7.4 minutes.
Standard deviation =
A)Approximately what percent of the completion times is between 73.4 and 88.2 minutes i.e.P(73.4<x<88.2)
Formula :
At x = 73.4
Z=0
Refer the z table for p value
p value = 0.5
At z = 88.2
Z=2
Refer the z table for p value
p value =0.9772
So,P(73.4<x<88.2)=0.9772-0.5=0.4772
So, 47.72% of the completion times is between 73.4 and 88.2 minutes
B)Approximately what percent of the completion times is at most 58.6 minutes i.e. ?
Z=-2
Refer the z table for p value
p value =0.0228
So,2.28% of the completion times is at most 58.6 minutes