The magnitudes of the major earthquakes in 1999 are listed below.
$\begin{array} { l l l }
\text { 1/19/99 } & \text { New Ireland, Papua New Guinea } & 7 \
2 / 6 / 99 & \text { Santa Cruz Islands, S.Pacific Sea } & 7.3 \
3 / 4 / 99 & \text { Celebes Sea, Indonesia } & 7.1 \
4 / 5 / 99 & \text { New Britain, Papua New Guinea } & 7.4 \
4 / 8 / 99 & \text { E.Russia/N.E.China border } & 7.1 \
5 / 10 / 99 & \text { New Britain, Papua New Guinea } & 7.1 \
5 / 16 / 99 & \text { New Britain, Papua New Guinea } & 7.1 \
8 / 17 / 99 & \text { Izmit region, western Turkey } & 7.4 \
9 / 21 / 99 & \text { Taiwan } & 7.8 \
9 / 30 / 99 & \text { Oaxaca, Mexico } & 7.4 \
11 / 12 / 99 & \text { Bolu Province, northwest Turkey } & 7.2
\end{array}$
Find the mean, median, and mode of the magnitudes. Round to the nearest tenth.
A) mean 7.2; mode 7; median 7.3
B) mean 7.3; mode 7.2; median 7.2
C) mean 7.4; mode 7.2; median 7.2
D) mean 7.3; mode 7.1; median 7.2
E) mean 7.2; mode 7.1; median 7.2

Question

The magnitudes of the major earthquakes in 1999 are listed below.
$\begin{array} { l l l } 
\text { 1/19/99 } & \text { New Ireland, Papua New Guinea } & 7 \
2 / 6 / 99 & \text { Santa Cruz Islands, S.Pacific Sea } & 7.3 \
3 / 4 / 99 & \text { Celebes Sea, Indonesia } & 7.1 \
4 / 5 / 99 & \text { New Britain, Papua New Guinea } & 7.4 \
4 / 8 / 99 & \text { E.Russia/N.E.China border } & 7.1 \
5 / 10 / 99 & \text { New Britain, Papua New Guinea } & 7.1 \
5 / 16 / 99 & \text { New Britain, Papua New Guinea } & 7.1 \
8 / 17 / 99 & \text { Izmit region, western Turkey } & 7.4 \
9 / 21 / 99 & \text { Taiwan } & 7.8 \
9 / 30 / 99 & \text { Oaxaca, Mexico } & 7.4 \
11 / 12 / 99 & \text { Bolu Province, northwest Turkey } & 7.2
\end{array}$
Find the mean, median, and mode of the magnitudes. Round to the nearest tenth.
A) mean 7.2; mode 7; median 7.3
B) mean 7.3; mode 7.2; median 7.2
C) mean 7.4; mode 7.2; median 7.2
D) mean 7.3; mode 7.1; median 7.2
E) mean 7.2; mode 7.1; median 7.2

Quizplus · Accepted Answer

To find the mean, add all the magnitudes and divide by the total number of earthquakes:
$$\frac{7+7.3+7.1+7.4+7.1+7.1+7.1+7.4+7.8+7.4+7.2}{11}\approx7.3$$
To find the median, order the magnitudes from least to greatest:
$$7,7.1,7.1,7.1,7.2,7.3,7.4,7.4,7.8$$
The median is the middle value, which is 7.2.
To find the mode, determine which magnitude appears most frequently. In this case, both 7.1 and 7.4 appear twice, so there are two modes: 7.1 and 7.4. The best choice is D, which has the mean and median rounded to 7.3 and 7.2, respectively, and the mode as 7.1.

The Magnitudes of the Major Earthquakes in 1999 Are Listed