Do drivers follow the posted speed limit of 65 mph on Interstate 270? The following data...
- Do drivers follow the posted speed limit of 65 mph on Interstate 270? The following data give the speeds (mph), as measured by radar, of 10 randomly selected cars traveling on Interstate 270:
|
76 |
72 |
80 |
68 |
76 |
74 |
71 |
78 |
82 |
64 |
Assume all conditions are met for confidence intervals.
- Find a 99% confidence interval for the population mean speed of all drivers on I-270. [3]
- Find a 95% confidence interval for the population mean speed of all drivers on I-270. [3]
- Find a 90% confidence interval for the population mean speed of all drivers on I-270. [3]
- As your confidence level decreased what happened to your confidence interval? [2]
- Write a sentence interpreting your 90% confidence interval in the context of this problem. [3]
- Based on your confidence interval in (e), do you think drivers follow the posted speed limit of 65 mph on Interstate 270? Explain. [3]
- How could we change this study so that the margin of error in our confidence interval decreases without adjusting the confidence level? [2]
Homework Answers
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Do drivers follow the posted speed limit of 65 mph on
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