Final answer:
The probability of selecting a defective DVR from the inventory of 100 DVRs, where 7 are known to be defective, is 0.07, or 7%.
Step-by-step explanation:
In the scenario where there are 100 digital video recorders (DVRs) and 7 are known to be defective, we seek to calculate the probability that a randomly chosen DVR is defective. Probability is calculated as the number of favorable outcomes divided by the total number of possible outcomes. In this case, there are 7 defective DVRs (favorable outcomes) and 100 DVRs in total (possible outcomes).
To find the probability of selecting a defective DVR, we use the formula:
P(defective) = Number of defective DVRs / Total number of DVRs
P(defective) = 7 / 100
Therefore, the probability of selecting a defective DVR is 0.07 or 7%.