Advertisements
Advertisements
Question
A school has 4 sections of Chemistry in class X having 40, 35, 45 and 42 students. The mean marks obtained in Chemistry test are 50, 60, 55 and 45 respectively for the 4 sections. Determine the overall average of marks per student.
Solution
Here n1 = 40, n2 = 35, n3 = 45, n4 = 42, `bar"X"_1 = 50, bar"X"_2 = 60, bar"X"_3 = 55 and bar"X"_4 = 45`.
∴ `bar"X" = ("n"_1bar"X"_1 + "n"_2bar"X"_2 + "n"_3bar"X"_3 + "n"_4bar"X"_4)/("n"_1 + "n"_2 + "n"_3 + "n"_4)`
= `(40 xx 50 + 35 xx 60 + 45 xx 55 + 42 xx 45)/(40 + 35 + 45 + 42)`
= `(2000 + 2100 + 2475 + 1890)/(162)`
= `(8465)/(162)`
= 52·25
Hence, the overall average maeks of perstudents is 52·25.
APPEARS IN
RELATED QUESTIONS
The following table gives the frequency distribution of trees planted by different Housing Societies in a particular locality:
| No. of Trees | No. of Housing Societies |
| 10-15 | 2 |
| 15-20 | 7 |
| 20-25 | 9 |
| 25-30 | 8 |
| 30-35 | 6 |
| 35-40 | 4 |
Find the mean number of trees planted by Housing Societies by using ‘Assumed Means Method’
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 |
Find the mean of each of the following frequency distributions: (5 - 14)
| Class interval | 0 - 6 | 6 - 12 | 12 - 18 | 18 - 24 | 24 - 30 |
| Frequency | 6 | 8 | 10 | 9 | 7 |
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 frequency distribution table using a suitable method:
| Class | 20 – 30 | 30 – 40 | 40 – 50 | 50 – 60 | 60 - 70 |
| Frequency | 25 | 40 | 42 | 33 | 10 |
There are three dealers A, B and C in Maharashtra. Suppose, the trade of each of them in september 2018 was as shown in the following table.
The rate of GST on each transaction was 5%.
Read the table and answer the questions below it.
| Dealer | GST collected on the sale |
GST paid at the time of purchase |
ITC | Tax paid to the Govt. |
Taxbalance with the Govt. |
| A | Rs.5000 | Rs. 6000 | Rs. 5000 | Rs. 0 | Rs. 1000 |
| B | Rs 5000 | Rs. 4000 | Rs. 4000 | Rs. 1000 | Rs. 0 |
| C | Rs.5000 | Rs. 5000 | Rs. 5000 | Rs. 0 | Rs. 0 |
(i) How much amount did the dealer A get by sale ?
(ii) For how much amount did the dealer B buy the articles ?
(iii) How much is the balance of CGST and SGST left with the government that was paid by A ?
There are 50 students in a class in which 40 are boys and rest are girls. The average weight of the class is 44 kgs and the average weight of the girls is 40 kgs. Find the average weight of the boys.
There is a grouped data distribution for which mean is to be found by step deviation method.
| Class interval | Number of Frequency (fi) | Class mark (xi) | di = xi - a | `u_i=d_i/h` |
| 0 - 100 | 40 | 50 | -200 | D |
| 100 - 200 | 39 | 150 | B | E |
| 200 - 300 | 34 | 250 | 0 | 0 |
| 300 - 400 | 30 | 350 | 100 | 1 |
| 400 - 500 | 45 | 450 | C | F |
| Total | `A=sumf_i=....` |
Find the value of A, B, C, D, E and F respectively.
An aircraft has 120 passenger seats. The number of seats occupied during 100 flights is given in the following table:
| Number of seats | 100 – 104 | 104 – 108 | 108 – 112 | 112 – 116 | 116 – 120 |
| Frequency | 15 | 20 | 32 | 18 | 15 |
The following table gives the marks scored by a set of students in an examination. Calculate the mean of the distribution by using the short cut method.
| Marks | Number of Students (f) |
| 0 – 10 | 3 |
| 10 – 20 | 8 |
| 20 – 30 | 14 |
| 30 – 40 | 9 |
| 40 – 50 | 4 |
| 50 – 60 | 2 |
