Dr. steve is working with a new radioactive substance in his lab. he currently has 64 grams of the substance and knows that it decays at a rate of 25% every hour.

identify whether this situation represents exponential growth or decay. then determine the rate of growth or decay, r, and identify the initial amount, a.
now write an equation to find how long it will take for the mass of the radioactive substance to reach 27 grams. then, solve the equation to find the answer.

Apoll is being conducted at a mall nothingto obtain a sample of the population of an entire country. what is the frame for this type of​ sampling? who would be excluded from the survey and how might this affect the results of the​ survey? what is the frame for this type of​ sampling? a. the frame is people who need new clothes. b. the frame is people who shop at the mall. c. the frame is people who like to shop. d. the frame is the entire population of the country. who would be excluded from the survey and how might this affect the results of the​ survey? a. any person that does not need new clothes is excluded. this could result in sampling bias due to undercoverage. b. any person who does not shop at the mall is excluded. this could result in sampling bias due to undercoverage. c. any person who does not shop at the mall is excluded. this could result in nonresponse bias due to people not participating in the poll. d. there is nobody that is being excluded from the survey.