Let $A(x)=\int_{0}^{x} f(t) d t$ for $f(x)$ in the following figure. Calculate $A(1.5), A(3), A^{\prime}(1.5)$, and $A^{\prime}(3)$. (Use decimal notation. Give your answers to one decimal place if needed.)

Step 1 ：Let $A(x)=\int_{0}^{x} f(t) d t$ for $f(x)$ in the following figure.

Step 2 ：Without the actual figure or a description of the function $f(x)$, it's impossible to calculate these values.

Step 3 ：We need more information about the function $f(x)$.

Step 4 ：\(\boxed{\text{Without the actual figure or a description of the function } f(x), \text{ it's impossible to calculate these values. We need more information about the function } f(x).}\)