Required information In a sample of 80 light bulbs, the mean lifetime was 1217 hours with a standard deviation of 51 hours. Someone says that the mean lifetime is less than 1220 hours. With what level of confidence can this statement be made? (Express the final answer as a percent and round to two decimal places.) The level of confidence is 0 %.

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.