'by a reasonable margin' is correct and usable in written English.
You can use it to refer to a difference between two items or values that is considered to be relatively large. For example, "The incumbent candidate won the election by a reasonable margin."
He said: "Borrowing looks set to be higher than the OBR forecast in March, possibly by a reasonable margin.
From these figures, the GRNN model outperformed the model (Glaso 1985) by a reasonable margin.
And thus to reach its past total valuation heights, its share price will have to pass its former record levels by a reasonable margin.
Some Canadian observers claimed Virtue and Moir had been under-marked in their short dance on Sunday - but Davis and White produced a peerless free dance to add Olympic gold to their 2013 world title, by a reasonable margin.
For reactions R5PI and RUPE, the absolute difference between our current model predictions and the values reported by Goldberg et al. (25) is within a reasonable margin, 0.21 and 0.07 kJ/mol, respectively.
It starts with a reasonable margin, but after all the costs of handling the product, Amazon loses $1 a pack.
But the administration added that "the cost of the contraceptive coverage could include a reasonable margin," or profit, for insurers.
His deficit is 2min 38sec; it is, as the French saying goes, a little and a lot at the same time: a reasonable margin of safety but no more.
Asked his opinion on what margin of profits would be expected from Channel 4 if it was expected to compete commercially, Abraham said: "20%to30%0% would be a reasonable margin, at a minimum.
Nevertheless, the present analysis may be useful to determine a reasonable margin in an institution.
The factors described above lead us to conclude that the perchlorate RfD derived by the NAS and now on IRIS (U.S. EPA 2005) is higher than what is needed to protect public health with a reasonable margin of safety.
