STATISTICAL TECHNIQUES AND TOOLS
CONFIDENCE INTERVALS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A 90% confidence interval for the mean speed driven by cars on Due West Road is given by (21, 45). What was the margin of error of this study?
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12
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24
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33
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None of these.
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Explanation:
Detailed explanation-1: -To get a 90% confidence interval, we must include the central 90% of the probability of the normal distribution. If we include the central 90%, we leave out a total of = 10% in both tails, or 5% in each tail, of the normal distribution.
Detailed explanation-2: -Answer and Explanation: FALSE. In general, the interval width increases with the confidence level. So, a 95% confidence interval would be wider than a 90% confidence interval.
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