Advertisements
Advertisements
Question
If the mean of the following distribution is 2.6, then the value of y is:
| Variable (x) | 1 | 2 | 3 | 4 | 5 |
| Frequency | 4 | 5 | y | 1 | 2 |
Options
3
8
13
24
Solution
8
Explanation:
Consider the following table:
| Variable (x) | Frequency (f) |
fx |
| 1 | 4 | 4 |
| 2 | 5 | 10 |
| 3 | y | 3y |
| 4 | 1 | 4 |
| 5 | 2 | 10 |
| ∑f = 12 + y | ∑fx = 28 + 3y |
Now,
Mean = `(sum"fx")/(sum"f")`
`2.6/1 = (28 + 3y)/(12+y)`
31.2 + 2.6y = 28 + 3y
3y – 2.6y = 31.2 – 28
0.4y = 3.2
y = `(3.2)/(0.4)`
y = 8
RELATED QUESTIONS
In a retail market, fruit vendors were selling mangoes kept in packing boxes. These boxes contained varying number of mangoes. The following was the distribution of mangoes according to the number of boxes.
| Number of mangoe | 50 − 52 | 53 − 55 | 56 − 58 | 59 − 61 | 62 − 64 |
| Number of boxes | 15 | 110 | 135 | 115 | 25 |
Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?
Find the value of p, if the mean of the following distribution is 20.
| x | 15 | 17 | 19 | 20+P | 23 |
| f | 2 | 3 | 4 | 5P | 6 |
Five coins were simultaneously tossed 1000 times and at each toss the number of heads were observed. The number of tosses during which 0, 1, 2, 3, 4 and 5 heads were obtained are shown in the table below. Find the mean number of heads per toss.
| No. of heads per toss | No. of tosses |
| 0 | 38 |
| 1 | 144 |
| 2 | 342 |
| 3 | 287 |
| 4 | 164 |
| 5 | 25 |
| Total | 1000 |
The arithmetic mean of the following data is 14. Find the value of k
| x1 | 5 | 10 | 15 | 20 | 25 |
| f1 | 7 | k | 8 | 4 | 5 |
Compute the mean for following data:
| Class | 1-3 | 3-5 | 5-7 | 7-9 |
| Frequency | 12 | 22 | 27 | 19 |
Find the mean of the following data using step-deviation method:
| Class | 500 – 520 | 520 – 540 | 540 – 560 | 560 – 580 | 580 – 600 | 600 – 620 |
| Frequency | 14 | 9 | 5 | 4 | 3 | 5 |
Which measure of central tendency is given by the x-coordinate of the point of intersection of the 'more than' ogive and 'less than' ogive?
Find the mean of the following distribution:
| x | 4 | 6 | 9 | 10 | 15 |
| f | 5 | 10 | 10 | 7 | 8 |
The distribution given below shows the runs scored by batsmen in one-day cricket matches. Find the mean number of runs.
| Runs scored |
0 – 40 | 40 – 80 | 80 – 120 | 120 – 160 | 160 – 200 |
| Number of batsmen |
12 | 20 | 35 | 30 | 23 |
250 apples of a box were weighed and the distribution of masses of the apples is given in the following table:
| Mass (in grams) |
80 – 100 | 100 – 120 | 120 – 140 | 140 – 160 | 160 – 180 |
| Number of apples |
20 | 60 | 70 | x | 60 |
Find the value of x and the mean mass of the apples.
