To find the mean number of hours spent on screens, you need to sum up all the hours and then divide by the total number of kids surveyed.
The data provided is: {0, 7, 8, 8, 10, 11, 14, 15, 17, 17.5, 18, 18, 18, 20, 30}
First, let's calculate the sum of these numbers:
\[ 0 + 7 + 8 + 8 + 10 + 11 + 14 + 15 + 17 + 17.5 + 18 + 18 + 18 + 20 + 30 = 0 + 7 + 8 + 8 + 10 + 11 + 14 + 15 + 17 + 17.5 + 18 + 18 + 18 + 20 + 30 \]
Calculating step-by-step:
- First, sum the integers: \[ 0 + 7 + 8 + 8 + 10 + 11 + 14 + 15 + 17 + 17 + 18 + 18 + 18 + 20 + 30 = 177.5 \]
Now let's calculate the mean:
The number of kids surveyed is 15, so the mean is calculated as follows:
\[ \text{Mean} = \frac{\text{Sum of hours}}{\text{Number of kids}} = \frac{177.5}{15} \]
Calculating the division:
\[ \frac{177.5}{15} \approx 11.833\ldots \]
Rounding this to the nearest tenth gives us:
\[ 11.8 \]
Thus, the mean number of hours spent on screens by the kids that the director surveyed is 11.8 hours.