A cell phone company is offering 2 different monthly plans. Each plan charges a monthly fee pulls an additional cost per gigabyte of data used. Plan A: $50 fee plus $7.50 per gigabyte of data
Plan B: $60 fee plus $5.00 per gigabyte of data
a.
Write an expression to represent the cost of Plan A.
b.
Write an expression to represent the cost of Plan B.
C.
Which plan would be the least expensive for someone who uses 6 gigabytes of data

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