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20 Aug 2025, 10:26
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Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
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0% (00:00) wrong based on 1 sessions
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The weights of python snakes are normally distributed with a mean of 110 kg and a standard deviation of 8 kg. If 68% of pythons weigh within one standard deviation of the mean and 95% of pythons weigh within two standard deviations of the mean, what percent of pythons weigh from 94 to 102 kg?
A. 47.5%
B. 34%
C. 27%
D. 17%
E. 13.5%
A. 47.5%
B. 34%
C. 27%
D. 17%
E. 13.5%
30 Aug 2025, 04:44
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Official Explanation
If 68% of pythons weigh within 1 standard deviation of the mean and 95% weigh within 2 standard deviations of the mean, then the difference 95% - 68% = 27% weigh between 1 and 2 standard deviations from the mean. Here, each standard deviation equals 8 kg, so 1 to 2 standard deviations correspond to 8 to 16 kg. Pythons weighing from 8 to 16 kg from the mean of 110, would have weights in either the interval 94 to 102, if they are below average, or in the interval 118 to 126, if they are above average. The question asks what percentage weigh between 94 and 102 kg, which matches the lower interval, and is therefore half of the 27%, or 13.5%, choice (E).
Answer: E
If 68% of pythons weigh within 1 standard deviation of the mean and 95% weigh within 2 standard deviations of the mean, then the difference 95% - 68% = 27% weigh between 1 and 2 standard deviations from the mean. Here, each standard deviation equals 8 kg, so 1 to 2 standard deviations correspond to 8 to 16 kg. Pythons weighing from 8 to 16 kg from the mean of 110, would have weights in either the interval 94 to 102, if they are below average, or in the interval 118 to 126, if they are above average. The question asks what percentage weigh between 94 and 102 kg, which matches the lower interval, and is therefore half of the 27%, or 13.5%, choice (E).
Answer: E
