Soru

Zorluk: OrtaMeasures of Central Tendency

A damage control officer is reviewing the completion times (in minutes) for various emergency response drills. Match each statistical description on the left with its correctly calculated value on the right.

  • Mean of the drill times 12,18,15,11,12, 18, 15, 11, and 1414 minutes1414
  • Median of the drill times 9,14,8,13,16,9, 14, 8, 13, 16, and 1212 minutes12.512.5
  • Mode of the drill times 10,15,12,10,18,10,10, 15, 12, 10, 18, 10, and 1414 minutes1010
  • Fourth drill time needed to achieve a mean of 1515 minutes, if the first three times are 16,12,16, 12, and 1414 minutes1818

Cevap

Mean pairs with 14; Median pairs with 12.5; Mode pairs with 10; Missing drill time pairs with 18.
Each statistical operation maps strictly to one correct outcome. Calculating the arithmetic mean gives 14, evaluating the sorted middle yields 12.5, counting frequencies identifies 10 as the mode, and algebraic substitution for a target mean resolves to 18.

Adım Adım Çözüm

1
Calculate the mean of the first data set.
12+18+15+11+14=7012 + 18 + 15 + 11 + 14 = 70. 70÷5=1470 \div 5 = 14.
The mean requires summing all given values and dividing by the count of the values.
2
Calculate the median of the second data set.
Sorted list: 8,9,12,13,14,168, 9, 12, 13, 14, 16. The median is (12+13)÷2=12.5(12 + 13) \div 2 = 12.5.
The median is the exact middle value. For an even number of data points, it is the average of the two middle numbers in a sorted list.
3
Identify the mode of the third data set.
The number 1010 appears three times, which is more than any other number.
The mode is the value that occurs most frequently in the distribution.
4
Calculate the missing value for the fourth scenario.
Total needed: 15×4=6015 \times 4 = 60. Current sum: 16+12+14=4216 + 12 + 14 = 42. Missing value: 60−42=1860 - 42 = 18.
To achieve a specific mean, the total sum must equal the mean multiplied by the number of events. Subtracting known events yields the missing event.

Anahtar Kavram

Measures of Central Tendency

Alternatif Yöntem

To find the missing drill time for a target mean of 15, you can use the deviation method: 16 is (+1), 12 is (-3), and 14 is (-1). The sum of these deviations is -3. To balance the average, the missing value must counteract this with an opposite deviation of +3. Therefore, the missing value is 15 + 3 = 18.
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