Question

The department of transportation has mandated that the average speed of cars no interstate
highways be no more than 70 km per hours in order. To check that the people follow it or
not, a researcher took a random sample of 186 cars and found that the average speed was 68
km per hours with a standard deviation 0.6 km per hours.
(a) Find the standard error of the mean
(b) Construct the interval around the sample mean that would contain the population mean
95% of the time.
(c) If the researcher wants to test that the true mean speed on its highways is 70 km per hours
or less with 95% confidence then
(i) State null and alternative hypotheses
(ii) Name the test which is suitable in this situation and why?
(iii)Calculate the value of test statistic and critical value.
(iv)Draw the conclusion on the basis of the applied test.

Answer 1

Answer:

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