Question

select the correct answer. in an attempt to be environmentally friendly, the city council decides that there must be at least 18 trees on each block in the city. a sample of 20 blocks was randomly surveyed, with these results (number of trees per block): 24, 17, 7, 20, 28, 27, 10, 21, 30, 8, 30, 27, 22, 27, 27, 13, 27, 20, 24, 17. what is the sample mean number of trees per block $\bar{x}$? a. there is insufficient data to answer this question. b. 17.7 c. 21.3 d. 24

Explanation:

Step1: Recall sample - mean formula

The formula for the sample mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $n$ is the sample size and $x_{i}$ are the individual data - points.

Step2: Identify $n$ and sum the data

Here, $n = 20$, and the data points are $24,17,7,20,28,27,10,21,30,8,30,27,22,27,27,13,27,20,24,17$.
$\sum_{i = 1}^{20}x_{i}=24 + 17+7+20+28+27+10+21+30+8+30+27+22+27+27+13+27+20+24+17$
$=426$.

Step3: Calculate the sample mean

$\bar{x}=\frac{\sum_{i = 1}^{20}x_{i}}{n}=\frac{426}{20}=21.3$.

Answer:

C. 21.3