Math Problem Statement

Sara wonders what percentage of her students answered at least half of the quiz questions incorrectly.

The relative cumulative frequency of students who earned a score of 20 or lower on the quiz is __________ .

34%

14%

68%

28%

Sara wonders what percentage of her students answered at least half of the quiz questions incorrectly. The relative cumulative frequency of students who earned a score of 20 or lower on the quiz is __________ .

Solution

To solve this, we need to focus on the histogram provided and analyze the dataTo solve this, we need to focus on the histogram provided and analyze the

The problem asks for the relative cumulative frequency of students who earned a score of 20 or lower.

Step-by-step approach:

  1. Look at the intervals for scores 20 or lower:

    • 1–5: Frequency = 4
    • 6–10: Frequency = 8
    • 11–15: Frequency = 15
    • 16–20: Frequency = 7
  2. Sum the frequencies for scores ≤ 20: 4+8+15+7=344 + 8 + 15 + 7 = 34

  3. Total frequency (i.e., total number of students): Add all frequencies from the histogram: 4+8+15+7+7+3+4+2=504 + 8 + 15 + 7 + 7 + 3 + 4 + 2 = 50

  4. Calculate the relative cumulative frequency for scores 20 or lower: 3450×100=68%\frac{34}{50} \times 100 = 68\%

Thus, the relative cumulative frequency of students who earned a score of 20 or lower is 68%.

Answer: 68%

Do you want further details on this calculation or have any questions?

Here are 5 related questions:

  1. How do you interpret cumulative frequency in a histogram?
  2. What is the difference between frequency and relative frequency?
  3. How can you calculate the median score using this histogram?
  4. What is the significance of choosing 20 as the cutoff for this quiz?
  5. How would the cumulative frequency change if the quiz had more questions?

Tip: To find relative cumulative frequency, always divide the cumulative frequency by the total and multiply by 100 to express it as a percentage.

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Math Problem Analysis

Mathematical Concepts

Cumulative Frequency
Relative Frequency
Histogram Interpretation

Formulas

Cumulative Frequency = Sum of Frequencies for Specified Range
Relative Frequency = (Cumulative Frequency / Total Frequency) * 100

Theorems

None (basic arithmetic and interpretation of histograms)

Suitable Grade Level

Grades 7-9