Answer:
The probability that it would take more than four hours to construct a soapbox derby car = 0.1587 or 15.87[tex]\%[/tex]
Step-by-step explanation:
Given -
Mean [tex](\nu )[/tex] = 3 hours
Standard deviation [tex](\sigma )[/tex] = 1 hours
Let X be the no of hours to construct a soapbox derby car
the probability that it would take more than four hours to construct a soapbox derby car =
[tex]P(X > 4)[/tex] = [tex]P(\frac{X - \nu }{\sigma}> \frac{4 - 3 }{1})[/tex]
= [tex]P(Z > 1)[/tex] Put [tex](Z = \frac{X - \nu }{\sigma})[/tex]
= 1 - [tex]P(Z < 1)[/tex]
= 1 - .8413 Using z table
= 0.1587
