Question

which day was the weather forecast most accurate?

forecast vs actual temperature

day	degrees above (+) or below (–) forecast
tuesday	–6
wednesday	+7
thursday	–2

○ monday
○ tuesday
○ wednesday
○ thursday

Explanation:

Step1: Understand accuracy measure

To find the most accurate forecast, we need to find the day with the smallest absolute difference between forecast and actual temperature. The absolute value of a number \( x \) is \( |x|=

$$\begin{cases}x, & x\geq0\\-x, & x < 0\end{cases}$$

\).

Step2: Calculate absolute differences

• For Monday: \( | + 4|=4 \)
• For Tuesday: \( |- 6| = 6 \)
• For Wednesday: \( |+7|=7 \)
• For Thursday: \( |-2| = 2 \)

Step3: Compare absolute differences

We compare the values \( 4,6,7,2 \). The smallest value is \( 2 \), which corresponds to Thursday.

Answer:

Thursday (the option: Thursday)