Question

Gas prices in a metropolitan area range from $2.75 to $3.18 with an average of $2.93. Use the range rule of thumb to estimate the standard deviation. a. 0.108 b. 0.215 c. 0.063 d. 0.012

Answer 1

We should know that:

The range rule of thumb is a handy method of estimating the range from the standard deviation. It tells us that the range is generally about four times the standard deviation.

So, the range of gas prices = 3.18 - 2.75 = 0.43

So, the standard deviation = range divided by 4 = 0.43 /4 = 0.1075 ≈ 0.108 (to the nearest 3 decimals )

so, the answer is option a. 0.108