Advertisements
Advertisements
Question
Arithmetic mean of 15 observations was calculated as 85. In doing so an observation was wrongly taken as 73 for 28. What would be correct mean?
Advertisements
Solution
Arithmetic mean = `"Sum of all observations"/"Number of observations"`
85 = `"Sum of 15 observations"/15`
85 × 15 = sum of 15 observations
1275 = sum of 15 observations
Wrong observation = 73
Correct observation = 28
∴ Correct Mean = `"Sum − Wrong value + Correct value"/"Number of observations"`
= `(1275 - 73 + 28)/15`
= `(1202 + 28)/15`
= `1230/15`
= 82
Correct mean = 82
APPEARS IN
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 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.
The mean height of 11 students in a group is 150 cm. The heights of the students are 154 cm, 145 cm, Y cm, Y + 4 cm, 160 cm, 151 cm, 149 cm, 149 cm, 150 cm, 144 cm and 140 cm. Find the value of Y and the heights of two students?
Find the mean of the following data.
5.1, 4.8, 4.3, 4.5, 5.1, 4.7, 4.5, 5.2, 5.4, 5.8, 4.3, 5.6, 5.2, 5.5
The mean of first fifteen even numbers is ____________
Find the mean of first 10 prime numbers and first 10 composite numbers
Let x, y, z be three observations. The mean of these observations is ______.
Mean of the data is always from the given data.
Mean of the observations can be lesser than each of the observations.
Calculate the Mean, Median and Mode of the following data:
5, 10, 10, 12, 13.
Are these three equal?
