Math Problem Statement

A lecturer asked students in his class to estimate their body weight (kg). The following data were obtained: Students: 92: 115: 52: 90: 65: 80: 85

Students 75: 97: 87: 63: 87: 85: 97: 85: 95

a. Calculate the mean and median of each!

b. Calculate the variance, standard deviation, and CC!

Solution

Let's break down the problem and solve it step by step.

Given dataLet's break down the problem and solve it step by step.

Given

The body weights (in kg) of the students are:

  • First group: 92, 115, 52, 90, 65, 80, 85
  • Second group: 75, 97, 87, 63, 87, 85, 97, 85, 95

(a) Mean and Median of Each Group

Group 1: 92, 115, 52, 90, 65, 80, 85
Group 2: 75, 97, 87, 63, 87, 85, 97, 85, 95

Mean Formula:

Mean=xin\text{Mean} = \frac{\sum x_i}{n}

Where xi\sum x_i is the sum of all the values, and nn is the number of values.

Median Formula:

For an odd number of data points, the median is the middle value when sorted. For an even number, the median is the average of the two middle values.

(b) Variance, Standard Deviation, and Coefficient of Variation

Variance Formula:

Variance=(ximean)2n\text{Variance} = \frac{\sum (x_i - \text{mean})^2}{n}

Standard Deviation (SD) Formula:

Standard Deviation=Variance\text{Standard Deviation} = \sqrt{\text{Variance}}

Coefficient of Variation (CC or CV):

Coefficient of Variation=Standard DeviationMean×100\text{Coefficient of Variation} = \frac{\text{Standard Deviation}}{\text{Mean}} \times 100

I'll now calculate these values.### Results:

Group 1: 92, 115, 52, 90, 65, 80, 85

  • Mean: 82.71 kg
  • Median: 85.0 kg
  • Variance: 350.20 kg²
  • Standard Deviation: 18.71 kg
  • Coefficient of Variation (CV): 22.62%

Group 2: 75, 97, 87, 63, 87, 85, 97, 85, 95

  • Mean: 85.67 kg
  • Median: 87.0 kg
  • Variance: 108.44 kg²
  • Standard Deviation: 10.41 kg
  • Coefficient of Variation (CV): 12.16%

Would you like more details or have any further questions?

Related Questions:

  1. How does variance affect the spread of data in each group?
  2. Why is the standard deviation higher in Group 1 compared to Group 2?
  3. How does the Coefficient of Variation help compare variability between groups?
  4. What can the difference in means tell us about the groups?
  5. How does skewness affect the median and mean in these datasets?

Tip: The coefficient of variation (CV) is useful for comparing the degree of variation between datasets with different means.

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Math Problem Analysis

Mathematical Concepts

Descriptive Statistics
Measures of Central Tendency
Variance
Standard Deviation
Coefficient of Variation

Formulas

Mean = sum(x) / n
Median = middle value (or average of middle two values)
Variance = sum((x - mean)^2) / n
Standard Deviation = sqrt(variance)
Coefficient of Variation = (standard deviation / mean) * 100

Theorems

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Suitable Grade Level

Grades 9-12