the following table shows the number of police calls that were made last year in each of the cities in…

Explanation:

Step1: Recall mean formula

The mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $n$ is the number of data - points and $\sum_{i = 1}^{n}x_{i}$ is the sum of the data - points. Here $n = 5$, and $\bar{x}=273$.

Step2: Calculate the sum of known data

The sum of the number of police calls in Clarksville, Bremington, Shells, and Gristle is $244 + 353+235 + 311=1143$.

Step3: Let the number of calls in Thornbury be $x$.

We know that $\bar{x}=\frac{1143 + x}{5}$, and $\bar{x}=273$. So we can set up the equation $\frac{1143 + x}{5}=273$.

Step4: Solve the equation for $x$

Multiply both sides of the equation by 5: $1143 + x=273\times5$. $273\times5 = 1365$, so $1143+x = 1365$. Subtract 1143 from both sides: $x=1365 - 1143$. $x = 222$.

Answer:

222