Question

a group of high school students worked part - time jobs over the summer. their weekly earnings are shown in the dot plot. what is the mean of their earnings? $130, $150, $153, $160

Explanation:

Step1: Count the number of data points

From the dot plot:

• $130: 1$ dot
• $140: 2$ dots
• $150: 3$ dots
• $160: 2$ dots
• $170: 1$ dot
• $180: 1$ dot

Total number of data points $n = 1 + 2 + 3 + 2 + 1 + 1 = 10$

Step2: Calculate the sum of all earnings

Sum $S = (130\times1) + (140\times2) + (150\times3) + (160\times2) + (170\times1) + (180\times1)$

$S = 130 + 280 + 450 + 320 + 170 + 180$

$S = 130 + 280 = 410$; $410 + 450 = 860$; $860 + 320 = 1180$; $1180 + 170 = 1350$; $1350 + 180 = 1530$

Step3: Calculate the mean

Mean $\bar{x} = \frac{S}{n} = \frac{1530}{10} = 153$

Answer:

$\$153$