Grammar. Not "a measures"

Existing Wording:

For a given facility and time period, a measures can be aggregated in different ways depending on the scoring of the measure. The scoring of measures implies the way that which rate aggregation can be performed:

Proposed Wording:

For a given facility and time period, a measures can be aggregated in different ways depending on the scoring of the measure. The scoring of measures implies the way that which rate aggregation can be performed: