To see which option is correct let's test each one.
[ The means are the same value. ]
To find the mean of a data set you add all the numbers then divide by the amount of numbers there are.
Project A:
5 + 5 + 10 + 10 + 10 + 15 + 15 + 15 + 20 + 25 = 130
There are 10 numbers on this dot plot.
130 / 10 = 13
Thus, the mean for Project A is 13.
Project B:
5 + 5 + 5 + 10 + 10 + 15 + 15 + 15 + 20 + 25 = 125
There are 10 numbers on this dot plot.
125 / 10 = 12.5
Thus, the mean for Project B is 12.5.
The mean's are different so this option is incorrect.
[ Both dot plots show the same range. ]
To find the range of a data set you subtract the highest number to the lowest number that was plotted on the plot.
Project A:
The lowest number that was plotted was 5 and the highest number that was plotted was 25.
25 - 5 = 20
Thus, the range of Project A is 20.
Project B:
The lowest number that was plotted was 5 and highest number that was plotted was 25.
25 - 5 = 20
Thus, the range of Project B is 20.
The range's are the same so this option is correct.
[ The medians for both dot plots are 15 e-mails. ]
To find the median of a data set you find the middle number of the data set.
Project A:
5, 5, 10, 10, 10, 15, 15, 15, 20, 25
Since there isn't a perfect middle number in this data set we need to find the middle of the two middle numbers. (10 and 15)
Thus, the median for Project A is 12.5.
Project B:
5, 5, 5, 10, 10, 15, 15, 15, 20, 25
Since there isn't a perfect middle number in this data set we need to find the middle of the two middle numbers. (10 and 15)
Thus, the median for Project A is 12.5.
Note that the answer choice says the median for both projects is "15". So, this option is incorrect.
[ The modes are the same value. ]
To find the mode of a data set you find the number that occurs the most in the data set.
Project A:
5, 5, 10, 10, 10, 15, 15, 15, 20, 25
10 and 15 occur 3 times in the data set which is the most.
Thus, the mode for Project A is 10 and 15.
Project B:
5, 5, 5, 10, 10, 15, 15, 15, 20, 25
5 and 15 occur 3 times in the data set which is the most.
Thus, the mode for Project B is 5 and 15.
The modes are different so this option is incorrect.
After testing each answer choice, the correct answer is [Both dot plots show the same range.]
Best of Luck!
