189k views
4 votes
The 147 heights of males from a data set of body measurements vary from a low of 152.0 cm to a high of 192.5 cm. Use the range rule of thumb to estimate the standard deviations and compare

the result to the standard deviation of 12.22 cm calculated using the 147 heights. What does the result suggest about the accuracy of estimates of s found using the range rule of thumb? Assume the
estimate is accurate if it is within 1.7 cm.

1 Answer

7 votes

Answer:The range rule of thumb states that the standard deviation (s) is approximately equal to the range (R) divided by 4, where the range is the difference between the maximum and minimum values of a data set.

Using this formula, we can estimate the standard deviation of the heights as:

s = R / 4 = (192.5 - 152.0) / 4 = 20.625 / 4 = 5.156 cm

Comparing this estimate to the actual standard deviation of 12.22 cm, we see that the estimate is off by a factor of approximately 2.37.

Since the estimate is not within 1.7 cm of the actual standard deviation, it suggests that the range rule of thumb is not a very accurate way to estimate the standard deviation of this data set. The standard deviation calculated using the full set of data is much larger than the estimate, which means that the spread of the data is greater than what would be expected based on the range rule of thumb.

User ETO
by
8.2k points