The phrase "a more difficult set of" is correct and usable in written English.
It can be used when referring to a collection of items, tasks, or challenges that are more complex or challenging than another set.
Example: "In this course, we will tackle a more difficult set of problems to enhance our critical thinking skills."
Alternatives: "a tougher group of" or "a more challenging collection of".
If instead, as we all hope, we start returning to growth late this year or early next, ministers will face a more difficult set of choices.
In some ways, because Liberty's operations were focused so heavily in the all-but-deserted eastern half of the city, Mr. McDonald must confront a more difficult set of choices than most of his corporate peers.
A more difficult set of questions will arise in any attempt to assess the extent to which the danger of renewed unraveling of the market may exist, either under the current NRMP algorithm or under a student-offering version, as the market changes in response to changes in health care financing.
Mutually advantageous transactions present a more difficult set of problems.
More able respondents received a more difficult set of items than less able respondents.
PASADENA — Aris Yeghiazaryan couldn't have faced a more difficult set of circumstances Wednesday afternoon.
As compared with these studies, the present investigation was performed on a larger set of samples, a broader range of agents and in a more difficult setting, comprising sampling of small children at several health care units in a developing country.
For the more difficult set of concepts, chemical bonding, creating a visual explanation led to much larger gains than creating a verbal one for students both high and low in spatial ability.
The recently released PC shooter game Soldier of Fortune offers the best of both worlds: an easy setting, for unlimited saves at any time in a level, or a more difficult setting that limits the number of saves per level.
But they discussed these hopes in a more difficult setting.
Based on McCarley & Krebs (2000) and Krebs & Sinai (2002), we had assumed that a more difficult stimulus set (i.e., degraded quality of image and type of psychophysical task) would lead to higher capacity coefficient values for the algorithmically fused imagery.
