Class Size

Q. Mean of $50$ observations was found to be $80.4$. But later on, it was discovered that $96$ was misread as$69$ at one place. Find the correct mean.

1. $8.4$
2. $75.9$
3. $79$
4. $80.94$

Q. In a frequency distribution, mid-point of a class is 10 and class width is 6. The lower limit of the class is:

1. 6
2. 12
3. 8
4. 7

Q. Which of the following is the correct expression for lower class limit? ($m$ = class midpoint, $u$ = upper class limit, $l$ = lower class limit)

1. $l$ = $m$ - 2$u$
2. $l$ = $m$ -$u$
3. $l$ = 2$m$ +$u$
4. $l$ = 2$m$ -$u$

Q. If the class width is 5, the lower-class limit is 10, what will be the upper-class limit of the same class?

1. 30
2. 25
3. 20
4. 15