8342937124

SU PIAN BIN SAMAT AND C.J. EVANS

Fig. 2: The obsewed count-rate ofP-particles as a Junctian ojnumber of absorbingfoils (0-24). The best

slraight linę has Urn computed using 1-19 foils only.

TABLE 1

X²cal obiained by the Computer program for different angles of scattering in the Rutherford experimcnt.

Scattering angh Number included	es Dcscription	X^2cal	*p	Gradient (m ± Am)
21	all data	28.75	0.03	-4.299 ± 0.028
18	all dala except 3 smallest angles	11.23	0.77	-3.911 ± 0.093
17	all dala except 4 smallest angles	11.22	0.73	-3.914 ±0.102
16	all data except 5 smallest angles	10.91	0.67	-3.937 1 0.112
15	all data except 6 smallest angles	10.68	0.62	-3.962 ±0.121

* Probability that a value of x* £ X* cal should have arisen due to statistical errors only. Notę: the probability has expected value of 0.5.

o

ation of X“^cal , and its significance level, when different numbersofpointsare included. Itcan be seen that when the First point (x = 0) or when the

last few points (large x) are included. then x²cal in-

creases and the significance level of the fu becomes distinctly worse. Therefore, thedeviationsfrom the straight linę at smali and large x are statistically significant, and likely to have arisen from physical proceses, such as those suggested. Although ii point x = 1 may also appear to deviate from ^ straight linę, this difference is not statistically * nificant; likewise, the X² test gives no justificati' for rejecting the points x= 18 and 19.

The assumption of a Gaussian distribution errors in equation (2) will be valid for both of the experiments sińce, although the underlying sta:

80

PERT ANI RA VOL. 14 NO. 1.1991