Consider the following summary data on the modulus ofelasticity (3 106 psi) for lumber of three different grades[in close agreement with values in the article BendingStrength and Stiffness of Second-Growth Douglas-FirDimension Lumber (Forest Products J., 1991: 3543),except that the sample sizes there were larger]:Grade J xi. si1 10 1.63 .272 10 1.56 .243 10 1.42 .26Use this data and a significance level of .01 to test thenull hypothesis of no difference in mean modulus ofelasticity for the three grades.

● Chapter 2 Descriptive Statistics ○ Displaying out data ■ Graphic Displays for numeric data. ■ Dot Plot ● Start with a number line, put a dot for each observation ● Best for smaller data sets ■ Family with 5 Children ages 1, 1, 2, 4, 15 ● Create a number line ● Put a dot at one, so put two dots at one, put a dot at 2, a dot at 4, and a final dot at 15 ■ Dot plots provide a sense of where the dates are