Question

all 150 eighth - grade students at a local middle school were asked how many hours they studied. each row of the table represents one sample from the population. find the mean of each sample.
population data
row 1 6 5 3 0 4
row 2 4 5 3 5 6
row 3 7 1 4 5 3
row 4 4 2 5 6 3
which row has the greatest mean?
row 1
row 2
row 3
row 4

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 $n = 5$.

Step2: Calculate mean for Row 1

$\sum_{i=1}^{5}x_{i}=6 + 5+3 + 0+4=18$. Mean of Row 1, $\bar{x}_1=\frac{18}{5}=3.6$.

Step3: Calculate mean for Row 2

$\sum_{i = 1}^{5}x_{i}=4 + 5+3 + 5+6=23$. Mean of Row 2, $\bar{x}_2=\frac{23}{5}=4.6$.

Step4: Calculate mean for Row 3

$\sum_{i = 1}^{5}x_{i}=7 + 1+4 + 5+3=20$. Mean of Row 3, $\bar{x}_3=\frac{20}{5}=4$.

Step5: Calculate mean for Row 4

$\sum_{i = 1}^{5}x_{i}=4 + 2+5 + 6+3=20$. Mean of Row 4, $\bar{x}_4=\frac{20}{5}=4$.

Answer:

B. Row 2