Refer to Assignment Problem 22. The researchers used gas chromatographic analysis to extract and identify eight major volatile chemicals present in the host plants (tomato). They tested each of these chemicals separately using the same experimental design to determine whether dodder seedlings would preferentially orient their growth. Of 34 dodder plants tested with one of these chemicals, α-pinene (also present in pine resin, as its name suggests), 11 seedlings grew toward the volatiles, 6 grew away, 8 grew toward the left side, and 9 grew toward the right side. The authors compared these observed frequencies to those expected by the null hypothesis. Their test statistic was χ2=1.53.  They obtained P=0.68.  Answer the following questions:

a. What are the null and alternate hypotheses?

b. Their  test statistic has how many degrees of freedom? 

Based on these results, state whether each of the following statements is either true or false:

c. The observed frequencies are compatible with the proportional probability model.

d. The difference between the observed and expected frequencies is statistically significant.

e. The test statistic exceeds the critical value corresponding to α=0.05.

f. Dodder plants do not orient their growth toward the plant volatile α- pinene

g. There is no evidence that dodder plants orient their growth toward α- pinene.

h. The difference between the proportion of individuals that grow toward α-pinene  and that grow away from α-pinene  in the dodder population is small.

Transcribed Image Text:

a-pinene