The average speed of vehicles on an expressway is being studied. a. Suppose observation on 50 vehicles yielded a sample mean of 65 km/hr. Assume that the standard deviation of vehicle speed is known to be 6 km/hr. Determine the two-sided 99% confidence intervals of the mean speed. b. In part (a), how many additional vehicles' speed should be observed such that the mean speed can be estimated to within + 1 km/hr with 99% confidence? C. Suppose John and Mary are assigned to collect data on the speed of vehicles on this expressway. After each person has separately observed 10 vehicles, what is the probability that John's sample mean will exceed Mary's sample mean by 2 km/hr? d. Repeat part (c) if each person has separately observed 100 vehicles instead?
The average speed of vehicles on an expressway is being studied.
a.
Suppose observation on 50 vehicles yielded a sample mean of 65 km/hr. Assume that the standard deviation of vehicle speed is known to be 6 km/hr. Determine the two-sided 99% confidence intervals of the mean speed.
b.
In part (a), how many additional vehicles' speed should be observed such that the mean speed can be estimated to within + 1 km/hr with 99% confidence?
C.
Suppose John and Mary are assigned to collect data on the speed of vehicles on this expressway. After each person has separately observed 10 vehicles, what is the probability that John's sample mean will exceed Mary's sample mean by 2 km/hr?
d.
Repeat part (c) if each person has separately observed 100 vehicles instead?
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