An automobile manufacturer claims that its van has a 59.1 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the MPG for this van since it is believed that the van has an incorrect manufacturer's MPG rating. After testing 160 vans, they found a mean MPG of 59.5. Assume the variance is known to be 2.89. A level of significance of 0.1 will be used. Find the value of the test statistic. Round your answer to 2 decimal places.

Test statistic Z = 1.8099

Step-by-step explanation:

Step(i):-

Given that mean of the Population (μ) = 59.1 miles/gallon

Mean of the sample (x⁻ ) = 59.5

The standard deviation of the Population = 2.89

mean of the sample (n) = 160

Step(ii):-

Test statistic

              Z = 1.8099

Test statistic = 1.8099

the graph in the attached figure

step-by-step explanation:

we have

using a graphing tool

the graph in the attached figure

the roots are ( x-intercepts) x=-0.5,x=1,x=3

the y-intercept is the point (0,3)