The mean lifetime for cardiac stents is 8.9 years. a medical device company has implemented some improvements in the manufacturing process and hypothesizes that the lifetime is now longer. a study of 40 new devices reveals a mean lifetime of 9.7 years with a standard deviation of 3.4 years. is there statistical evidence of a prolonged lifetime of the stents?

Marco is studying a type of mold that grows at a fast rate. he created the function f(x) = 345(1.30)x to model the number of mold spores per week. what does the 1.30 represent? how many mold spores are there after 4 weeks? round your answer to the nearest whole number. 1.30 represents the number of mold spores marco had at the beginning of the study; 985 mold spores 1.30 represents the number of mold spores grown in a given week; 448 mold spores 1.30 represents the 30% rate of weekly growth; 345 mold spores 1.30 represents the 30% rate of weekly growth; 985 mold spores

What is the area of the triangle 10 13 12

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class