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The weights of 30 learners are: 22, 14, 18, 26, 32, 11, 29, 21, 15, 27, 34, 13, 24, 19, 20, 25, 25, 21, 10, 16, 28, 20, 17, 24, 12, 19, 22, 25, 33, 21. Construct a frequency distribution table using c

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3 parts
ii

20-24\text{20-24}

iii
21.5
iv

20-24\text{20-24}

Step 1: List the given data in ascending order.
The weights of the 30 learners are:
22, 14, 18, 26, 32, 11
29, 21, 15, 27, 34, 13
24, 19, 20, 25, 25, 21
10, 16, 28, 20, 17, 24
12, 19, 22, 25, 33, 21

Sorted data:
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 19, 20, 20, 21, 21, 21, 22, 22, 24, 24, 25, 25, 25, 26, 27, 28, 29, 32, 33, 34

i) Construct a frequency distribution table.
Using class intervals of 10-14, 15-19, 20-24, etc., we calculate the frequency (f), midpoint (x), product of frequency and midpoint (fx), and cumulative frequency (cf) for each class.

Class IntervalFrequency (f)Midpoint (x)fxCumulative Frequency (cf)
10-14512605
15-1961710211
20-2492219820
25-2972718927
30-343329630
Total∑f=30\sum f = 30∑fx=645\sum fx = 645

ii) Identify the modal class.
The modal class is the class interval with the highest frequency. From the table, the highest frequency is 9, which corresponds to the class interval 20-24.
The modal class is 20-24\boxed{\text{20-24}}.

iii) Calculate the mean weight of the learners.
The mean (xˉ\bar{x}) for grouped data is calculated using the formula:

xˉ=∑fx∑f\bar{x} = \frac{\sum fx}{\sum f}

From the frequency distribution table:
∑fx=645\sum fx = 645
∑f=30\sum f = 30

Substitute these values into the formula:

xˉ=64530\bar{x} = \frac{645}{30} xˉ=21.5\bar{x} = 21.5

The mean weight of the learners is 21.5\boxed{21.5}.

iv) Determine the median class.
The median class is the class interval where the median value lies.
The total number of learners (NN) is 30.
The position of the median is N2=302=15th\frac{N}{2} = \frac{30}{2} = 15^{th} value.
Looking at the cumulative frequency column:

  • The 5th value is in the 10-14 class.
  • The 11th value is in the 15-19 class.
  • The 20th value is in the 20-24 class. Since the 15th value falls between the 11th and 20th values, it is located in the 20-24 class. The median class is 20-24\boxed{\text{20-24}}.
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