We consider scalar-field power-law cosmology featuring homogeneous canonical scalar field and dust fluid evolving in
alatenon-flat FLRW universe expanding with power-law
function. The scalar field is minimally coupled to gravity
and dust fluids are baryonic and CDM perfect fluids. We
use two sets of observational data, combined WMAP5+
BAO+SN dataset and WMAP5 dataset, as the inputs. Mean
values of both sets suggest slightly closed geometry. With
k=+1, it gives mean value ofa0at 8.4×10
26
for WMAP5
and 1.9×10
27
for WMAP5+BAO+SN datasets. For
closed universe, the WMAP5 dataset puts the lower limit of
5.1×10
26
fora0while the WMAP5+BAO+SN dataset
puts the lower limit of 9.85×10
26
.TheWMAP5data
alone yields the exponentα=1.01 agreeing with the previous study ofH(z)data which givesα=1.07 (Dev et al.2008). However combined WMAP5+BAO+SN data disagrees with the previous combinedH(z)+SN Ia data, i.e.
WMAP5+BAO+SN givesα=0.985 whileH(z)+SN
givesα=2.28 (closed geometry) (Dev et al.2008).