Rubber rabbitbrush plants display heritable variation in plant height and insect-induced gall formation. In a field study, resea
rchers investigated the relationship between plant height and gall number for the rubber rabbitbrush plants in a natural population. The researchers used the data they collected to perform a chi-square test of independence. The null hypothesis for the chi-square test was that plant height and gall number are independent. The data for the chi-square test are presented in Table 1. Table 1. Data for the chi-square test of independence
Height Category (cm)(cm) Number of Plants with Ten or Fewer Galls Number of Plants with More than Ten Galls
0–30 34 6
31–60 22 16
61–90 14 21
91–120 10 27
The researchers calculated a chi-square value of 29.25. If there are three degrees of freedom and the significance level is p=0.05p=0.05, which of the following statements best completes the chi-square test?
The critical value is 0.05, and the null hypothesis cannot be rejected because the calculated chi-square value is greater than the critical value.
A. he critical value is 0.05, and the null hypothesis can be rejected because the calculated chi-square value is greater than the critical value.
B. The critical value is 7.82, and the null hypothesis cannot be rejected because the calculated chi-square value is greater than the critical value.
C. The critical value is 7.82, and the null hypothesis can be rejected because the calculated chi-square value is greater than the critical value.
