A grocery store manager plans to distribute coupons (10% off) to stimulate sales. However, recent research shows that marketing promotion may decrease sales. Specifically, only when a customer spends over $35.00 can such a promotional discount increase sales. To figure out whether distributing the coupon can increase sales (by examining the average consumer spendings), what test should the manager conduct?

A: two sample t-test

B: chi-square

C: ANOVA

D: one sample t-test