In a batch of 1160 calculators, 5 were found to be defective. what is the probability that a calculator chosen at random will be defective? write the probability as a percent. round to the nearest tenth of a percent if necessary.

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?