Question

use the chart of quiz scores to find the weighted mean. the weighted mean is \boxed{}. (round to the nearest tenth.) \

$$\begin{tabular}{|c|c|c|c|c|} \\hline quiz scores & 7 & 9 & 12 & 13 \\\\ \\hline frequency & 2 & 2 & 3 & 4 \\\\ \\hline \\end{tabular}$$

Explanation:

Step1: Calculate the sum of (score × frequency)

For score 7 and frequency 2: $7\times2 = 14$
For score 9 and frequency 2: $9\times2 = 18$
For score 12 and frequency 3: $12\times3 = 36$
For score 13 and frequency 4: $13\times4 = 52$

Sum these products: $14 + 18 + 36 + 52 = 120$

Step2: Calculate the total frequency

Sum the frequencies: $2 + 2 + 3 + 4 = 11$

Step3: Calculate the weighted mean

Weighted mean = $\frac{\text{Sum of (score × frequency)}}{\text{Total frequency}} = \frac{120}{11} \approx 10.9$

Answer:

10.9