9. There are 12 cell phone charging cords available at a store for purchase. The length of each charging cord in inches is reflected as 3, 3, 4, 6, 6, 6, 6, 7, 10, 10, 11, and 12, respectively. What are the mean of these data?
Answer: C
The mean of the charging cords is 7 inches.
To calculate the mean, you sum all the lengths of the charging cords and then divide by the total number of cords. The total length is 81 inches, and dividing by 12 gives a mean of 7 inches.
A) 8
Option A is incorrect because the mean of the lengths does not equal 8 inches. Summing the lengths (3 + 3 + 4 + 6 + 6 + 6 + 6 + 7 + 10 + 10 + 11 + 12) results in 81, and when divided by 12, the mean is 7, not 8.
B) 6
Option B is incorrect as well. While 6 is one of the lengths of the charging cords, it does not represent the average. The calculations show that the total length of 81 inches divided by 12 results in a mean of 7 inches, which is significantly higher than 6.
C) 7
Option C is correct because it accurately represents the mean length of the charging cords. The calculation of the total length (81 inches) divided by the number of cords (12) yields exactly 7 inches.
D) 9
Option D is incorrect. The mean cannot be 9 inches as it is not supported by the summation and division of the total lengths. The average calculated from the available data is 7 inches, making 9 an inaccurate representation of the mean.
Conclusion
The mean of the charging cords is definitively 7 inches, as calculated from the total length and divided by the number of cords. Options A, B, and D fail to reflect this accurate calculation, thereby confirming that C is the only correct answer.