Math Problem Statement

Find the mean of students' scores based on the grouped frequency distribution table.

Solution

To find the mean of the students' scores from the given table, we’ll use the concept of a grouped frequency distribution. Here are the steps:

  1. Identify the Midpoint (Class Mark) for Each Score Range: The midpoint for each range is calculated by averaging the lower and upper limits.
  2. Multiply Each Midpoint by its Frequency to get the total for each range.
  3. Sum of the Products: Add up all the products obtained from step 2.
  4. Sum of Frequencies: Add up all the frequencies.
  5. Calculate the Mean using the formula:

Mean=(Midpoint×Frequency)Frequency\text{Mean} = \frac{\sum ( \text{Midpoint} \times \text{Frequency})}{\sum \text{Frequency}}

Calculations

Score RangeFrequency (ff)Midpoint (xx)f×xf \times x
76 – 803783×78=2343 \times 78 = 234
71 – 754734×73=2924 \times 73 = 292
66 – 708688×68=5448 \times 68 = 544
61 – 65106310×63=63010 \times 63 = 630
56 – 60125812×58=69612 \times 58 = 696
51 – 556536×53=3186 \times 53 = 318

Summing Up

  • Sum of f×xf \times x: 234+292+544+630+696+318=2714234 + 292 + 544 + 630 + 696 + 318 = 2714
  • Sum of Frequencies (ff): 3+4+8+10+12+6=433 + 4 + 8 + 10 + 12 + 6 = 43

Mean Calculation

Mean=27144363.14\text{Mean} = \frac{2714}{43} \approx 63.14

The mean score of the students is approximately 63.14.

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Related Questions

  1. How would you calculate the median score from this grouped data?
  2. What does the mean score tell us about the students' performance?
  3. How can we calculate the mode for grouped data like this?
  4. What is the significance of choosing the midpoint for each range in finding the mean?
  5. How would the mean change if the frequencies for the score ranges were altered?

Tip

In grouped frequency distributions, the midpoint approximation gives a close estimate of the central tendency but may not be exact since individual scores within the ranges are not known.

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Math Problem Analysis

Mathematical Concepts

Statistics
Mean
Grouped Frequency Distribution
Central Tendency

Formulas

Mean = (Σ (Midpoint × Frequency)) / Σ Frequency

Theorems

Grouped Frequency Distribution

Suitable Grade Level

Grades 7-9