Math Problem Statement

Following are the number of items of similar type produced in a factory during the last 50 days. 21 22 17 23 27 15 16 22 15 23 24 25 36 19 14 21 24 25 14 18 20 31 22 19 18 20 21 20 36 18 21 20 31 22 19 18 20 20 24 35 25 26 19 32 22 26 25 26 27 22 Arrange these observations into a frequency distribution with both inclusive and exclusive class intervals choosing a suitable number of classes.

Solution

To arrange the given observations into a frequency distribution, both with inclusive and exclusive class intervals, we need to follow these steps:

  1. Find the Range:

    • The range is the difference between the maximum and minimum values.
    • Maximum value = 36
    • Minimum value = 14
    • Range = 36 - 14 = 22
  2. Determine the Number of Classes:

    • The number of classes is usually determined by the Sturges' formula: Number of classes=1+3.322×log10(n)\text{Number of classes} = 1 + 3.322 \times \log_{10}(n) where nn is the number of observations.
    • For n=50n = 50: Number of classes=1+3.322×log10(50)1+3.322×1.6996.647\text{Number of classes} = 1 + 3.322 \times \log_{10}(50) \approx 1 + 3.322 \times 1.699 \approx 6.64 \approx 7
    • So, we will use 7 classes.
  3. Determine the Class Width:

    • Class width = RangeNumber of classes=2273.14\frac{\text{Range}}{\text{Number of classes}} = \frac{22}{7} \approx 3.14
    • Rounding up to the nearest whole number, we get a class width of 4.
  4. Form the Class Intervals:

    • For inclusive class intervals, each class will be of the form [a,b][a, b].
    • For exclusive class intervals, each class will be of the form [a,b)[a, b).

Inclusive Class Intervals:

Let's start from the minimum value (14) and create intervals of width 4.

  • 14 - 17
  • 18 - 21
  • 22 - 25
  • 26 - 29
  • 30 - 33
  • 34 - 37

Now, we tally the observations into these intervals:

Class IntervalFrequency
14 - 177
18 - 2112
22 - 2516
26 - 297
30 - 334
34 - 374

Exclusive Class Intervals:

For exclusive class intervals, the first interval will be [14, 18) and so on:

  • 14 - 18
  • 18 - 22
  • 22 - 26
  • 26 - 30
  • 30 - 34
  • 34 - 38

Now, tally the observations:

Class IntervalFrequency
14 - 1812
18 - 2219
22 - 2616
26 - 307
30 - 344
34 - 382

Summary

  • Inclusive Class Intervals:

    • 14 - 17: 7
    • 18 - 21: 12
    • 22 - 25: 16
    • 26 - 29: 7
    • 30 - 33: 4
    • 34 - 37: 4
  • Exclusive Class Intervals:

    • 14 - 18: 12
    • 18 - 22: 19
    • 22 - 26: 16
    • 26 - 30: 7
    • 30 - 34: 4
    • 34 - 38: 2

Would you like more details or have any questions?

Here are some related questions to consider:

  1. What are the advantages of using inclusive class intervals over exclusive ones?
  2. How would the frequency distribution change if the class width were different?
  3. How do you calculate the cumulative frequency for the intervals?
  4. What is the importance of choosing an appropriate number of classes?
  5. How would you graphically represent this frequency distribution?

Tip: When constructing frequency distributions, always consider the nature of your data and choose class intervals that effectively summarize the data without losing important details.

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Math Problem Analysis

Mathematical Concepts

Statistics
Frequency Distribution
Class Intervals

Formulas

Sturges' formula for determining number of classes

Theorems

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Suitable Grade Level

High School