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The heights of a group of students are normally distributed with a mean of 160 cm and a standard deviation of 10 cm. What is the range of heights that includes approximately 99.7% of the students in this group?

(a) 140 cm to 180 cm
(b) 130 cm to 190 cm
(c) 120 cm to 200 cm
(d) 110 cm to 210 cm

User Roepit
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1 Answer

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Final answer:

The range of heights that includes approximately 99.7% of the students is 130 cm to 190 cm, according to the empirical rule for a normal distribution with a mean of 160 cm and a standard deviation of 10 cm. Option B is the correct answer.

Step-by-step explanation:

To determine the range of heights that includes approximately 99.7% of the students in this group, you can apply the empirical rule, sometimes referred to as the 68-95-99.7 rule. This rule states that for a normal distribution, about 68% of the data falls within one standard deviation of the mean, about 95% falls within two standard deviations, and about 99.7% falls within three standard deviations. Since the mean height is 160 cm and the standard deviation is 10 cm:

  • One standard deviation from the mean ranges from 150 cm to 170 cm (which includes about 68% of the data).
  • Two standard deviations from the mean ranges from 140 cm to 180 cm (which includes about 95% of the data).
  • Three standard deviations from the mean ranges from 130 cm to 190 cm (which includes about 99.7% of the data).

Therefore, the range of heights that includes approximately 99.7% of the students is 130 cm to 190 cm, which corresponds to option (b).

The correct answer to the question, "What is the range of heights that includes approximately 99.7% of the students in this group?" is (b) 130 cm to 190 cm.

User Egur
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