Advertisements
Advertisements
Question
Find the mean of each of the following frequency distributions
| Classes | 25 - 29 | 30 - 34 | 35 - 39 | 40 - 44 | 45 - 49 | 50 - 54 | 55 - 59 |
| Frequency | 14 | 22 | 16 | 6 | 5 | 3 | 4 |
Solution
Let the assume mean A = 42
| Classes | Mid value(x1) | d1 = x1 - 42 | `"u"_1=(x1-42)/5` | f1 | f1u1 |
| 25 - 29 | 27 | -15 | -3 | 14 | -42 |
| 30 - 34 | 32 | -10 | -2 | 22 | -44 |
| 35 - 39 | 37 | -5 | -1 | 16 | -16 |
| 40 - 44 | 42 | 0 | 0 | 6 | 0 |
| 45 - 49 | 47 | 5 | 1 | 5 | 5 |
| 50 - 54 | 52 | 10 | 2 | 3 | 6 |
| 55 - 59 | 57 | 15 | 3 | 4 | 12 |
| N = 70 | `sumf_1"u"_1=-79` |
We have
A = 42, h = 5
Mean `=A+hxx(sumf_1"u"_1)/N`
`=42+5xx(-79)/70`
`=42+(-395)/70`
`=42-395/70`
= 42 - 5.643
= 36.357
APPEARS IN
RELATED QUESTIONS
Find the mean of each of the following frequency distributions
| Class interval | 0 - 10 | 10 - 20 | 20 - 30 | 30 - 40 | 40 - 50 |
| Frequency | 9 | 12 | 15 | 10 | 14 |
Find the mean of the following frequency distribution is 57.6 and the total number of observation is 50.
| Class | 0-20 | 20-40 | 40-60 | 60-80 | 80-100 | 100-120 |
| Frequency | 7 | `f_1` | 12 | `f_2` | 8 | 5 |
Find the correct answer from the alternatives given.
The formula to find mean from a grouped frequency table is \[X = A + \frac{\sum f_i u_i}{\sum f_i} \times hg\] .
The mean of 1, 3, 4, 5, 7, 4 is m. The numbers 3, 2, 2, 4, 3, 3, p have mean m − 1 and median q. Then, p + q =
If the mean of observation \[x_1 , x_2 , . . . . , x_n is x\] then the mean of x1 + a, x2 + a, ....., xn + a is
The following table shows the weight of 12 students:
| Weight in kg. | 67 | 70 | 72 | 73 | 75 |
| Number of students | 4 | 3 | 2 | 2 | 1 |
Find the Mean weight.
The median from the table is?
| Value | Frequency |
| 7 | 2 |
| 8 | 1 |
| 9 | 4 |
| 10 | 5 |
| 11 | 6 |
| 12 | 1 |
| 13 | 3 |
If xi’s are the midpoints of the class intervals of grouped data, fi’s are the corresponding frequencies and `barx` is the mean, then `sum(f_ix_i - barx)` is equal to ______.
Is it true to say that the mean, mode and median of grouped data will always be different? Justify your answer
Find the values of x and y if the mean and total frequency of the distribution are 25 and 50 respectively.
| Class Interval | 0 – 10 | 10 – 20 | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 |
| Frequency | 7 | x | 5 | y | 4 | 2 |
