Math Problem Statement

Find the mean, median, mode, and population standard deviation of the following data set: 19, 23, 25, 28, 30, 32, 33, 33.

Solution

Let’s solve this problem step by step:

Given Data:

19, 23, 25, 28, 30, 32, 33, 33

1. Mean:

The mean is calculated as: Mean=Sum of all valuesNumber of values\text{Mean} = \frac{\text{Sum of all values}}{\text{Number of values}} Sum=19+23+25+28+30+32+33+33=243\text{Sum} = 19 + 23 + 25 + 28 + 30 + 32 + 33 + 33 = 243 Mean=2438=30.4\text{Mean} = \frac{243}{8} = 30.4

2. Median:

The median is the middle value(s) when the data is ordered. Since there are 8 values (an even number): Median=4th value + 5th value2\text{Median} = \frac{\text{4th value + 5th value}}{2} Median=28+302=29.0\text{Median} = \frac{28 + 30}{2} = 29.0

3. Mode:

The mode is the most frequently occurring value(s). In the dataset:

  • 33 appears twice, while all other values appear once. Mode=33\text{Mode} = 33

4. Population Standard Deviation:

The formula for population standard deviation is: σ=(xiμ)2N\sigma = \sqrt{\frac{\sum{(x_i - \mu)^2}}{N}} Where:

  • xix_i = each data value,
  • μ\mu = mean,
  • NN = number of values.

Step 1: Calculate deviations from the mean (xiμx_i - \mu): μ=30.4\mu = 30.4

&19 - 30.4 = -11.4,\; 23 - 30.4 = -7.4,\; 25 - 30.4 = -5.4,\; 28 - 30.4 = -2.4, \\ &30 - 30.4 = -0.4,\; 32 - 30.4 = 1.6,\; 33 - 30.4 = 2.6,\; 33 - 30.4 = 2.6 \end{aligned}$$ **Step 2**: Square these deviations: $$(-11.4)^2 = 129.96,\; (-7.4)^2 = 54.76,\; (-5.4)^2 = 29.16,\; (-2.4)^2 = 5.76$$ $$(-0.4)^2 = 0.16,\; (1.6)^2 = 2.56,\; (2.6)^2 = 6.76,\; (2.6)^2 = 6.76$$ **Step 3**: Sum of squared deviations: $$129.96 + 54.76 + 29.16 + 5.76 + 0.16 + 2.56 + 6.76 + 6.76 = 235.88$$ **Step 4**: Divide by $$N = 8$$: $$\frac{235.88}{8} = 29.485$$ **Step 5**: Square root: $$\sigma = \sqrt{29.485} \approx 5.4$$ ### Final Answers: - **Mean**: $$30.4$$ - **Median**: $$29.0$$ - **Mode**: $$33$$ - **Population Standard Deviation**: $$5.4$$ Would you like me to explain any step in more detail or perform further calculations? --- ### 5 Related Questions: 1. What is the difference between population and sample standard deviation? 2. Can there be more than one mode in a dataset? 3. How would the mean and median change if another 33 was added to the dataset? 4. Why is the standard deviation important in understanding data spread? 5. How can we calculate variance from the standard deviation? ### Tip: Always arrange data in ascending order first when finding the median or mode—it ensures clarity and accuracy!

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Math Problem Analysis

Mathematical Concepts

Statistics
Mean
Median
Mode
Standard Deviation

Formulas

Mean = (Sum of all values) / (Number of values)
Median = (4th value + 5th value) / 2 (for even number of values)
Mode = the most frequent value
Population Standard Deviation = sqrt( (sum of (xi - mean)^2) / N )

Theorems

Central Limit Theorem

Suitable Grade Level

Grades 9-12