Please do not just copy someone else's answer. They are incorrect and not complete.

What is the predictive density of a new observation at the predictor vector x = (1,0.12.0.56)?

y	x1	x2	x3
-1.47196	1	-0.62645	-0.38342
4.585642	1	1.595281	1.215549
3.113337	1	0.487429	0.562698
1.018829	1	-0.30539	0.239762
-0.21683	1	-0.62124	-1.09928
1.817658	1	-0.04493	-0.03631
4.314445	1	0.821221	0.753025
1.144786	1	0.782136	0.569865
2.500895	1	0.619826	0.417039
-2.69653	1	-1.47075	-1.17297
5.02527	1	1.35868	0.920239
0.026614	1	-0.05381	-0.45078
1.017648	1	-0.39429	-0.2938
2.757856	1	0.763176	0.484866
2.360044	1	0.696963	0.654873
-0.03233	1	-0.7075	-0.38587
1.359103	1	-0.11235	0.18569
-1.6795	1	-0.61203	-0.32608
5.096062	1	1.433024	1.597237
-1.7833	1	-1.04413	-0.55998
8.162335	1	2.401618	1.66936
1.041416	1	0.028002	-0.20338
-3.28047	1	-1.80496	-0.8238
6.298758	1	2.172612	1.663481
1.115098	1	0.610726	0.147279
1.655023	1	0.291446	0.071025
0.455197	1	0.074341	-0.12482
-0.53512	1	-0.13518	0.258801
3.76664	1	0.593946	0.515647
0.556808	1	-0.30418	-0.10192

y = XB + 0, assuming o = 1 is known, and 3 has a multivariate normal prior with mean 0 and covariance matrix 100(X'X)-. y = XB + 0, assuming o = 1 is known, and 3 has a multivariate normal prior with mean 0 and covariance matrix 100(X'X)