Final answer:
The statement regarding the influence of seasonal patterns on indirect cost rates over longer time periods is false. Seasonal variations tend to average out over longer time frames, although businesses should use multiple-year data for accuracy.
Step-by-step explanation:
When calculating indirect cost rates, the claim that the longer the time period, the greater the influence of seasonal patterns on the amount of costs is false. Seasonal patterns do affect costs in certain businesses, but this influence is often most pronounced over shorter periods when analyzing high and low seasons individually. Over longer periods, such as a year, these seasonal variations tend to average out, resulting in a smoother distribution of indirect costs. To ensure accurate indirect cost rates over time, businesses may analyze data from multiple years to mitigate the effects of any one atypical seasonal fluctuation.