Question

consider these sample data: $x_1 = 10,x_2 = 8,x_3 = 3,x_4 = 15$. a. find n. b. compute $sum x_i$. c. determine $\bar{x}$.

Explanation:

Step1: Count data - point number

The number of data - points $n$ is the number of values given. Here, we have $x_1,x_2,x_3,x_4$, so $n = 4$.

Step2: Calculate sum of data

To find $\sum_{i}x_i$, we add up all the data - points. So $\sum_{i}x_i=x_1 + x_2+x_3+x_4=10 + 8+3+15$.
$10 + 8+3+15=(10 + 8)+3+15=18+3+15=(18 + 3)+15=21+15 = 36$.

Step3: Determine sample mean

The sample mean $\bar{x}=\frac{\sum_{i}x_i}{n}$. We know that $\sum_{i}x_i = 36$ and $n = 4$, so $\bar{x}=\frac{36}{4}=9$.

Answer:

a. $n = 4$
b. $\sum_{i}x_i=36$
c. $\bar{x}=9$