Question

Julieta is using the dot plots to compare two sets of data. both plots use the same number line. what is the difference between the mean of each data set?

Answer 1

The answer is C, 9.

Explanation:

The dot plot is giving the numbers 2, 3, 5, 5, 5, 9, 11, 14,15,21

and the second gives 7, 12, 16,16,18,20,20,25,28.

To find the mean, you add all of the numbers together and divide by the number of numbers there are, so if you had 1, 2, and 3, you would do 1 + 2 + 3 divided by 3, which is 2.

2, 3, 5, 5, 5, 9, 11, 14,15,21 all added together is 162, and 7, 12, 16,16,18,20,20,25,28 is equal to 90. 162 divided by 9 (since there are nine numbers) is 18, and 90 divided by 10 is 9.

18 - 9 is 9.

Hence the answer of 9.

Hope this helps!

I know for a fact this is from a "source."

*wink* :< )

Answer 2

I think this problem has an accompanying dot plot but its missing. I'll just use an example of the dot plot.

The mean of the data set is the average of the data. You add up all the data then divide the sum by the number of data.

Number of households that have dogs. 2 blocks.
Block A
0 x 5 = 0
1 x 4 = 4
2 x 3 = 6
3 x 2 = 6
4 x 1 = 4
15 20
mean: 20 / 15 = 1.33

Block B
0 x 2 = 0
1 x 3 = 3
2 x 4 = 8
3 x 3 = 9
4 x 1 = 4
5 x 1 = 5
6 x 1 = 6
15 35
mean = 35/15 = 2.33

As you can see, they may lie in the same number line but their mean is different because their data is different. Block B has an average of 2 dogs per household while Block A has an average of 1 dog.