Question

class survey: how many siblings do you have? 1,1,0,2,2,3,4,0,3,2,4,1,2,1,6,2,3,1,1,1,0,0,1
4 use the survey data to complete the dot graph.
5 what is the median and the mean of the data?

Explanation:

Step1: Count data - points for dot - graph

Count the number of times each value (0, 1, 2, 3, 4, 6) appears in the data set 1, 1, 0, 2, 2, 3, 4, 0, 3, 2, 4, 1, 2, 1, 6, 2, 3, 1, 1, 1, 0, 0, 1.
0 appears 4 times, 1 appears 9 times, 2 appears 5 times, 3 appears 3 times, 4 appears 2 times, 6 appears 1 time.

Step2: Arrange data for median

Arrange the data in ascending order: 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 6. There are 24 data - points. The median for an even - numbered data set is the average of the $\frac{n}{2}$th and $(\frac{n}{2}+1)$th ordered values. $\frac{24}{2}=12$ and $\frac{24}{2}+1 = 13$. The 12th value is 1 and the 13th value is 1. So the median is $\frac{1 + 1}{2}=1$.

Step3: Calculate the mean

The sum of the data is $0\times4+1\times9 + 2\times5+3\times3+4\times2+6\times1=0 + 9+10 + 9+8+6=42$. The mean $\bar{x}=\frac{\sum_{i = 1}^{n}x_{i}}{n}$, where $n = 24$. So the mean is $\frac{42}{24}=\frac{7}{4}=1.75$.

Answer:

1. For the dot - graph: Place 4 dots above 0, 9 dots above 1, 5 dots above 2, 3 dots above 3, 2 dots above 4, and 1 dot above 6.
2. Median: 1, Mean: 1.75