The local police department attempted to estimate the average vehicle speed along a strip of the main street. Using a hidden radar, the speed of a random group of 32 vehicles was measured, yielding a sample average of 36 mph. Assume a population standard deviation of 4 mph Police are adding a new warning sign on Main Street, which they assume will reduce average speeds. The null hypothesis is that the new speed has not changed, with an average content of 36 mph and a standard deviation of 4 mph. After the sign is raised, the average speed of 4 vehicles is measured at 34 miles per hour. i. What is the z score of this change, under the sampling distribution of the null? ii. Should we use a one - tailed or two - tailed test? iii. What is the p value for this z score under this test?
The local police department attempted to estimate the average vehicle speed along a strip of the main street. Using a hidden radar, the speed of a random group of 32 vehicles was measured, yielding a sample average of 36 mph. Assume a population standard deviation of 4 mph Police are adding a new warning sign on Main Street, which they assume will reduce average speeds. The null hypothesis is that the new speed has not changed, with an average content of 36 mph and a standard deviation of 4 mph. After the sign is raised, the average speed of 4 vehicles is measured at 34 miles per hour.
i. What is the z score of this change, under the sampling distribution of the null?
ii. Should we use a one - tailed or two - tailed test?
iii. What is the p value for this z score under this test?
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