Answer:
a
The 95% confidence bounds is
b
It was not necessary to make any assumption about the shape of the travel time distribution
Step-by-step explanation:
From the question we are told that
The sample size is n = 30
The sample mean is
The standard deviation is
From the question we are told the confidence level is 95% , hence the level of significance is
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Generally from the normal distribution table the critical value of is
Generally the margin of error is mathematically represented as
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Generally 95% confidence bounds is mathematically represented as
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This 95% confidence bounds show that there is 95% confidence that the true mean lies within this bound hence there is it was not necessary to make any assumption about the shape of the travel time distribution