The number of hours, t, that bacteria spread 10-fold can be modeled by the equation B(t) = B0(10)2t. There are 15 bacteria present initially and a biologist wishes to find out how many hours will elapse until there are 1,845 bacteria present. What is the exact value for the number of hours elapsed, t, in the equation 1,845 = 15(10)2t? t equals start fraction log of one hundred twenty three over two end fraction
t equals start fraction log of one thousand eight hundred forty five over two times log of one hundred fifty end fraction
t equals start fraction log of one hundred twenty three over log of two end fraction
t equals start fraction log of one hundred eighty four point five over two times log of fifteen end fraction

Farmers know that driving heavy equipment on wet soil compresses the soil and injures future crops. here are data on the "penetrability" of the same type of soil at two levels of compression. penetrability is a measure of how much resistance plant roots will meet when they try to grow through the soil. compressed soil 2.85 2.66 3 2.82 2.76 2.81 2.78 3.08 2.94 2.86 3.08 2.82 2.78 2.98 3.00 2.78 2.96 2.90 3.18 3.16 intermediate soil 3.17 3.37 3.1 3.40 3.38 3.14 3.18 3.26 2.96 3.02 3.54 3.36 3.18 3.12 3.86 2.92 3.46 3.44 3.62 4.26 use the data, omitting the high outlier, to give a 95% confidence interval for the decrease in penetrability of compressed soil relative to intermediate soil. compute degrees of freedom using the conservative method. interval: to