The mean of the following data, using the assumed-mean method is ____.

Class	0-10	10-20	20-30	30-40	40-50
Frequency	7	10	15	8	10

Class

0-10

10-20

20-30

30-40

40-50

Frequency

7

10

15

8

10

Class Interval

Frequency, $f_i$

Mid-value, $x_i$

$u_i$=$\frac{x_i-A}{h}$=$\frac{x_i-25}{10}$

$f_i{u}_i$

0-10

7

5

-2

-14

10-20

10

15

-1

-10

20-30

15

25=A

0

0

30-40

8

35

1

8

40-50

10

45

2

20

Σ$f_i$=50

Σ$f_i{u}_i$=4