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# We calculated the 99% conﬁdence interval for the average age of runners in the 2014 London...

We calculated the 99% conﬁdence interval for the average age of runners in the 2014 London Marathon as (263.5237, 283.472) based on a sample of 100 runners. How could we decrease the width of this interval without losing conﬁdence?

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