A bus company advertised a mean time of 150 minutes for a trip between two cities. A consumer group had reason to believe that the mean time was more than 150 minutes. A sample of 40 trips showed a...

A bus company advertised a mean time of 150 minutes for a trip between two cities. A consumer group had reason to believe that the mean time was more than 150 minutes. A sample of 40 trips showed a mean x̄=
153
minutes and a standard deviation of s=7.5
minutes.

Set significance level at
10%.

a) State the parameter of interest?

 State the
null
and
alternative hypothesis?

b) State the observed value.d) Verify conditions and calculate the value of the z-statistic?e) For what values of x̄ do we reject
the null?

c) Do we have sufficient evidence to say that the mean time is less than 150 minutes? Explain????