  We use the Fisher matrix formalism to predict the prospects of measuring the
redshifted 21-cm power spectrum in different $k$-bins using observations with
the upcoming Ooty Wide Field Array (OWFA) which will operate at $326.5 {\rm
MHZ}$. This corresponds to neutral hydrogen (HI) at $z=3.35$, and a measurement
of the 21-cm power spectrum provides an unique method to probe the large-scale
structures at this redshift. Our analysis indicates that a $5 \sigma$ detection
of the binned power spectrum is possible in the $k$ range $0.05 \leq k \leq 0.3
\, {\rm Mpc}^{-1}$ with $1,000$ hours of observation. We find that the
Signal-to-Noise ratio (${\rm SNR}$) peaks in the $k$ range $0.1- 0.2\, {\rm
Mpc}^{-1}$ where a $10 \sigma$ detection is possible with $2,000$ hours of
observations. Our analysis also indicates that it is not very advantageous to
observe much beyond $1,000$ hours in a single field of view as the ${\rm SNR}$
increases rather slowly beyond this in many of the small $k$-bins. The entire
analysis reported here assumes that the foregrounds have been completely
removed.
