Still living online the pew research poll described in exercise 5 found that 56% of a sample of 1060 teens go online several times a day. (treat this as a simple random sample.) a) find the margin of error for this poll if we want 95% confi-dence in our estimate of the percent of american teens who go online several times a day. b) explain what that margin of error means. c) if we only need to be 90% confident, will the margin of error be larger or smaller? explain. d) find that margin of error. e) in general, if all other aspects of the situation remain the same, would smaller samples produce smaller or larger margins of error?

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