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A random sample of 100 measurements of uncongested freeway driving speeds is taken. The results are...

A random sample of 100 measurements of uncongested freeway driving speeds is taken. The results are = 57.3 m.p.h. and s = 6.0 m.p.h. Construct a 95% confidence interval for the mean driving speed.

(a) Check the requirements for constructing 95% confidence interval for the mean yield per meter. Are the requirements satisfied?

(b) Construct and interpret a 95% confidence interval for the mean driving speed. Describe your work.

(c) Suppose we want to have the margin of error equal to 1%. What sample size do we need? (The critical z value for the 95% confidence level is 1.96)

Math   Statistics-And-Probability   
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