Marine biologists have noticed that the color of the outermost growth band on a clam tends to be related to the time of the year in which the clam dies. A biologist conducted a small investigation of whether this is true for the species Protoiluua staminea. She collected a sample of 78 clam shells from this species and cross-classified them according to (1) month when the clam died and (2) color of the outermost growth band. The data are shown in the following table.

(a) Create a stacked bar chart similar to Figure 10.5.1 to compare the color distribution across the 2 months.
(b) Create a summary table similar to Table 10.5.2 to compare the percentage distributions of colors across the 2 months.
(c) Use a chi-square test statistic for investigating whether color distribution is independent of month. Let α = 0.05, what is your conclusion regarding H0?
Figure 10.5.1

Transcribed Image Text:

Color Clear Dark Unreadable February 926 March Total 6 15 25 51 12 Table 10.5.1 Plover nest locations across 3 years Year Location Agricultural field (AF) 19 26 66 Prairie dog habitat (PD) 17 38 12 67 Grassland (G) Total 2004 2005 2006 Total 9 20 63 47 153 43