Your question was incomplete. Need to resubmit. The 68-95-99 probabilities correspond to 1, 2 and 3 standard deviations respectively. 68% of the time, chicks will hatch in 20 to 22 days, 95% of the time in 19 to 23 days, and 99% of the time in 18 to 24 days. Suggest you break the question into three parts.

68 over 7 as mixed number is 95/7

The empirical rule is 68 - 95 - 99.7. 68% is the area for +/- 1 standard deviation (SD) from the mean, 95% is the area for +/- 2 SD from the mean; and 99.7% is the area for +/- 3 SD from the mean.

what else do you want it to apply to

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