The number of books in different shelves of a library are as follows:
$37, 22, 24, 27, 28, 27, 20, 36, 21, 20,$
$29, 30, 29, 36, 30, 25, 27, 32, 24, 28,$
$34, 20, 25, 28, 30, 20, 35, 25, 27, 31$
Represent the data given above by a grouped frequency distribution table,taking the class intervals as $18-22, 22-26, 26-30, 30-34, 34-38$.

(N/A) To represent the data in a grouped frequency distribution table,we count the number of observations falling into each class interval. Note that the upper limit of a class is excluded from that class (e.g.,$18-22$ includes values from $18$ up to $21$).
$1$. For $18-22$: $20, 21, 20, 20, 20$ (Total: $5$)
$2$. For $22-26$: $22, 24, 25, 24, 25, 25$ (Total: $6$)
$3$. For $26-30$: $27, 28, 27, 27, 29, 29, 28, 28, 27$ (Total: $9$)
$4$. For $30-34$: $30, 30, 30, 32, 31$ (Total: $5$)
$5$. For $34-38$: $37, 36, 36, 34, 35$ (Total: $5$)

Number of books (Class)	No. of shelves (Frequency)
$18-22$	$5$
$22-26$	$6$
$26-30$	$9$
$30-34$	$5$
$34-38$	$5$