Question

It is known that the highest weekly average price for gasoline in California during 2005 was $3.15 per gallon and the lowest weekly average price for gasoline in California during 2005 was $2.56. Use this information to estimate the standard deviation of the weekly average price for gasoline in California during 2005. The standard deviation is ($3.15-2.56) / 6. I was wondering why you divide by 6?

Answer 1

Answer:

$0.15

Step-by-step explanation:

To solve this problem, we apply the Range rule for estimating Standard deviation.

By the Range Rule:

Standard Deviation

Highest weekly average price for gasoline= $3.15 per gallon.

Lowest weekly average price for gasoline =$2.56 per gallon.

Therefore:

$\text{Standard Deviation}\approx \dfrac{3.15-2.56}{4} \\=\dfrac{0.59}{4} \\\\=\ 0.15 (correct to the nearest cent).$

The standard deviation of the weekly average price for gasoline is approximately $0.15.

NOTE: You divide by 4 not 6.