Table 5.

Types of moulds and corresponding tests.

No.	Mixes	Natural Frequency (Hz)				S.D.
		Sample 1	Sample 2	Sample 3	Average
1	RFC	478	451	486	471.67	±18.34
2	SF/10%	469	427	433	443	±22.716
3	SF/5%	457	437	462	452	±13.23
4	SF/5%–5%/CR (400&180)	476	452	463	463.67	±12.01
5	SF/10%–5%/CR (400&180)	456	439	454	449.67	±9.29
6	SF/5%–10%/CR (400&180)	479	493	474	482	±9.85
7	SF/10%–10%/CR (400&180)	441	446	435	440.67	±5.51
8	SF/5%–5%/CR (75)	443	462	431	445	±15.63
9	SF/10%–5%/CR (75)	477	500	459	477	±20.55
10	SF/5%–10%/CR (75)	453	456	472	460	±10.21
11	SF/10%–10%/CR (75)	488	493	512	498	±12.66