The mean of marks scored by 100 students was found to be 40. later on, it was discovered that a score of 53 was misread as 83. find the correct mean.

As the sum of marks of others remain unchanged , let their sum be x . As the mean using 83 was 40 , we have ,

(x +83)/100 = 40

x + 83 = 4000

x = 3917

Now mean using 53 ,

(x +53)/100

(3917+53)/100

39.7.

Hope it helps , plz mark as brainiest :-)

(A)12-19

Step-by-step explanation:

To construct a frequency distribution, we follow the steps below.

1. Find the largest and smallest values.

91 and 12 respectively

Compute the Range = Maximum - Minimum=91-12=79

2. Determine the number of classes desired.

In this case, we desire 10 classes

3. Next, we find the class width by dividing the range by the number of classes and rounding up.

79÷10 = 7.9

Rounded Up, Class Width=8

4. Pick a suitable starting point less than or equal to the minimum value.

Since our minimum value is 12, we pick a class starting with 12 and give a class width of 8.

Therefore the upper and lower limits of the first class is given as:

12-19.