Question

the dot - plot shows the number of magazines sold. determine the mean of the data set.
a 19
b 20
c 21
d 22

Explanation:

Step1: Count data - points

Count number of dots for each value.

Step2: Calculate sum

Sum of (value * frequency). Let's assume frequencies: 17: 2, 18: 2, 19: 3, 20: 5, 21: 1, 22: 3, 23: 2, 24: 2, 25: 2. Sum = \(17\times2 + 18\times2+19\times3 + 20\times5+21\times1+22\times3+23\times2+24\times2+25\times2=400\). Total number of data - points = 20.

Step3: Find mean

Mean=\(\frac{400}{20}=20\).

Answer:

B. 20