Advertisements
Advertisements
Question
The following table shows the electricity (in units) used by 25 families of Eklara village in a month of May. Complete the table and answer the following questions.
| Electricity used (units) `bb(x_i)` |
No. of Families (frequency) `bb(f_i)` |
`bb(f_ix_i)` |
| 30 | 7 | _________ |
| 45 | 2 | __________ |
| 60 | 8 | __________ |
| 75 | 5 | __________ |
| 90 | 3 | __________ |
| N = _________ | `sum f_ix_i` = ______ |
- How many families use 45 units electricity?
- State the score, the frequency of which is 5.
- Find N, and `sum f_ix_i`
- Find the mean of electricity used by each family in the month of May.
Advertisements
Solution
| Electricity used (units) `bb(x_i)` |
No. of Families (frequency) `bb(f_i)` |
`bb(f_ix_i)` |
| 30 | 7 | 30 × 7 = 210 |
| 45 | 2 | 45 × 2 = 90 |
| 60 | 8 | 60 × 8 = 480 |
| 75 | 5 | 75 × 5 = 375 |
| 90 | 3 | 90 × 3 = 270 |
| N = 25 | `sum f_ix_i` = 1425 |
(1) 2 families use 45 units of electricity.
(2) The score with a frequency of 5 is 75 units.
(3) N = 25, and `sum f_ix_i`= 1425
(4) Since,
= `1425/25`
= 57
So, the mean of electricity used by each family in the month of May is 57.
RELATED QUESTIONS
Following table shows the points of each player scored in four games:
| Player | Game 1 | Game 2 | Game 3 | Game 4 |
| A | 14 | 16 | 10 | 10 |
| B | 0 | 8 | 6 | 4 |
| C | 8 | 11 | Did not play | 13 |
Now answer the following questions:
- Find the mean to determine A’s average number of points scored per game.
- To find the mean number of points per game for C, would you divide the total points by 3 or by 4? Why?
- B played in all the four games. How would you find the mean?
- Who is the best performer?
The data 6, 4, 3, 8, 9, 12, 13, 9 has mean 9.
If `barx` is the mean of x1, x2 ............xn and `bary` is the mean of y1, y2, …….yn and `barz` is the mean of x1, x2 ............xn, y1, y2, ……….yn then `barz` =?
The mean of five numbers is 50, out of which mean of 4 numbers is 46, find the 5th number:
Ashish studies for 4 hours, 5 hours, and 3 hours respectively on three consecutive days. How many hours does he study daily on average?
If the mean of five observations x, x + 2, x + 4, x + 6, x + 8, is 11, then the mean of first three observations is
The mean of a set of numbers is `bar(X)`. If each number is multiplied by z, the mean is
The mean of runs scored by a cricket team in the last 10 innings is 276. If the scores are 235, 400, 351, x, 100, 315, 410, 165, 260, 284, then find the runs scored in the fourth innings
Mean of the observations can be lesser than each of the observations.
Mean can never be a fraction.
