167k views
4 votes
The brain volumes (cm³) of 50 brains vary from a low of 906 cm³ to a high of 1498 cm³. Use the range rule of thumb to estimate the standard deviations and compare the result to the exact standard deviation of 171 cm³, assuming the estimate is accurate if it is within 15 cm³.

The estimated standard deviation is ​

User Juozas
by
8.0k points

2 Answers

7 votes

Answer:

The range rule of thumb suggests that the estimated standard deviation is approximately 18.2 cm³. This estimate is within 15 cm³ of the exact standard deviation of 171 cm³, indicating that it is accurate.

User Krishna Kishore
by
8.3k points
2 votes

Answer:

Explanation:

The range of the brain volumes is:

Range = highest value - lowest value = 1498 cm³ - 906 cm³ = 592 cm³

According to the range rule of thumb, the standard deviation can be estimated as:

Standard deviation ≈ Range / 4

Standard deviation ≈ 592 cm³ / 4 ≈ 148 cm³

The estimate of the standard deviation is within 15 cm³ of the exact standard deviation of 171 cm³, so it can be considered accurate according to the given criteria. However, note that the range rule of thumb is a very rough estimate and may not be very accurate in all cases.

User Brian Wylie
by
7.5k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories