The base of a solid right pyramid is a square with an edge length of n units. The height of the pyramid is n- 1 units. Which expression represents the volume of the pyramid? on(n - 1) units o nin - 1)2 units o 1n_n – 1) units o fn(n-1) units​

1. according to the internal revenue service, the mean tax refund for the year 2007 was $2,708. assume the standard deviation is $650 and that the amounts refunded follow a normal probability distribution. a. what percent of the refunds are more than $3,000? b. what percent of the refunds are more than $3,000 but less than $4,000? c. what percent of the refunds are less than $2,000?