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\( \begin{array}{lllllllllll}5.32 & 5.27 & 2.63 & 3.16 & 3.42 & 2.31 & 6.76 & 5.13 & 4.78 & 4.37 & 2.77 \\ 1.87\end{array} \) The range is 4.89 dollars. (Type an integer or decimal rounded to two decimal places as needed.) The variance is \( \square \) (Type an integer or decimal rounded to two decimal places as needed.)

Ask by Hart Best. in the United States
Feb 02,2025

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Answer

The variance is 2.07.

Solution

To calculate the variance of the given dataset, follow these steps: ### **Dataset:** \[ 5.32, \, 5.27, \, 2.63, \, 3.16, \, 3.42, \, 2.31, \, 6.76, \, 5.13, \, 4.78, \, 4.37, \, 2.77, \, 1.87 \] ### **Step 1: Calculate the Mean** \[ \text{Mean} = \frac{\sum x_i}{n} = \frac{5.32 + 5.27 + 2.63 + 3.16 + 3.42 + 2.31 + 6.76 + 5.13 + 4.78 + 4.37 + 2.77 + 1.87}{12} = \frac{47.79}{12} = 3.98 \] ### **Step 2: Calculate Each Squared Deviation from the Mean** \[ \begin{align*} (5.32 - 3.98)^2 &= 1.34^2 = 1.79 \\ (5.27 - 3.98)^2 &= 1.29^2 = 1.66 \\ (2.63 - 3.98)^2 &= (-1.35)^2 = 1.83 \\ (3.16 - 3.98)^2 &= (-0.82)^2 = 0.68 \\ (3.42 - 3.98)^2 &= (-0.56)^2 = 0.32 \\ (2.31 - 3.98)^2 &= (-1.67)^2 = 2.80 \\ (6.76 - 3.98)^2 &= 2.78^2 = 7.71 \\ (5.13 - 3.98)^2 &= 1.15^2 = 1.32 \\ (4.78 - 3.98)^2 &= 0.80^2 = 0.64 \\ (4.37 - 3.98)^2 &= 0.39^2 = 0.15 \\ (2.77 - 3.98)^2 &= (-1.21)^2 = 1.47 \\ (1.87 - 3.98)^2 &= (-2.11)^2 = 4.46 \\ \end{align*} \] ### **Step 3: Sum All Squared Deviations** \[ \sum (x_i - \text{Mean})^2 = 1.79 + 1.66 + 1.83 + 0.68 + 0.32 + 2.80 + 7.71 + 1.32 + 0.64 + 0.15 + 1.47 + 4.46 = 24.82 \] ### **Step 4: Calculate the Variance** \[ \text{Variance} = \frac{\sum (x_i - \text{Mean})^2}{n} = \frac{24.82}{12} = 2.07 \] ### **Final Answer:** \[ \boxed{2.07} \]

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To find the variance, we first need to calculate the mean (average) of the dataset. 1. **Calculate the Mean:** \[ \text{Mean} = \frac{5.32 + 5.27 + 2.63 + 3.16 + 3.42 + 2.31 + 6.76 + 5.13 + 4.78 + 4.37 + 2.77 + 1.87}{12} = \frac{43.68}{12} \approx 3.64 \] 2. **Calculate Each Deviation from the Mean and Square It:** \[ \begin{align*} (5.32 - 3.64)^2 & \approx 2.79 \\ (5.27 - 3.64)^2 & \approx 2.73 \\ (2.63 - 3.64)^2 & \approx 1.22 \\ (3.16 - 3.64)^2 & \approx 0.23 \\ (3.42 - 3.64)^2 & \approx 0.04 \\ (2.31 - 3.64)^2 & \approx 1.76 \\ (6.76 - 3.64)^2 & \approx 9.28 \\ (5.13 - 3.64)^2 & \approx 2.21 \\ (4.78 - 3.64)^2 & \approx 1.31 \\ (4.37 - 3.64)^2 & \approx 0.54 \\ (2.77 - 3.64)^2 & \approx 0.75 \\ (1.87 - 3.64)^2 & \approx 3.13 \\ \end{align*} \] 3. **Sum of Squared Deviations:** \[ 2.79 + 2.73 + 1.22 + 0.23 + 0.04 + 1.76 + 9.28 + 2.21 + 1.31 + 0.54 + 0.75 + 3.13 \approx 27.28 \] 4. **Calculate Variance:** \[ \text{Variance} = \frac{\text{Sum of Squared Deviations}}{N} = \frac{27.28}{12} \approx 2.27 \] Thus, the variance rounded to two decimal places is approximately **2.27**.

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