The management of discount furniture, a chain of discount furniture stores in the northeast, designed an incentive plan for salespeople. To evaluate this innovative plan, 12 Salespeople were selected at random, and their weekly incomes before and after the plan were recorded.
Sid: before $320, after $340
Carol: before $290, after $285
Tom: before $421, after $475
Andy: before $510, after $510
Jean: before $210, after $210
Jack: before $402, after $560
Peg: before $625, after $631
Anita: before $560, after $560
John: before $360, after $365
Carl: before $431, after $431
A.S.: before $506, after $525
Fern: before $505, after $619
Was there a significant increase in the typical salesperson's weekly income due to the innovative incentive plan? Use the .05 significance level. Estimate the p-value, and interpret it.