Calculate the mean and standard deviation for the following table given the age distribution of a group of people: Age: 20-30 30-40 40-50 50-60 60-70 70-80 80-90 No. of persons: 3 51 122 141 130 51 2

Explanation

To calculate the mean and standard deviation for the given age distribution, we will follow these steps:

### Step 1: Organize the Data
We have the following age groups and their corresponding frequencies:

| Age Group | Mid Value (x) | Frequency (f) |
|-----------|---------------|---------------|
| 20-30 | 25 | 3 |
...