t-models, part I Using the t tables, software, or a calculator, estimate a) the critical value of t for a 90% confidence interval with df = 17. b) the critical value of t for a 98% confidence interval with df = 88. c) the P-value for t 2.09 with 4 degrees of freedom. d) the P-value for _ t _ 7 1.78 with 22 degrees of freedom.

Statistics 201 9/06/16 Dispersion spread Info about location (avg or median) Range difference between max and min Range=maxmin Positive/right skew mean is pulled to the right, and is larger than the median Negative/left skew mean is pulled to the left, and is smaller than the median Symmetric/bell shaped mean is approximately the same as median IQR= Q Q3 1 is not effected by extreme values b/c os ca;culated using values that lie close to the center of the data set. IQR is not used in inferential statistics but are useful as descriptive statist