Person Before After 1 176 2 192 3 185 4 177 5 196 6 178 7 196 8 181 9 158 10 201 11 191 12 193 13 176 14 212 15 177 16 183 17 210 18 198 19 157 20

Refer to the Weight Watchers file.

Use Excel to test. For each paired difference, compute After – Before. In Data Analysis, t-Test: paired Two Sample for means, select the After data for Variable 1 Range. Note that the critical value output by Data Analysis for this test is always positive. In this problem, the sign of the critical value is negative corresponding to the 1-tailed test with lower reject region and negative lower critical value.

What is the critical t-value?

a.      7.861 or -7.861

b.     3.645 or -3.645

c.      1.711 or -1.711

d.     5.614 or -5.614