Most salamanders of the species P.cinereus are red striped, but some individuals are all red. The all-red form is thought to be a mimic of the salamander N.viridescens, which is toxic to birds. In order to test whether the mimic form actually survives more successfully, 163 striped and 41 red individuals of P.cinereus were exposed to predation by a natural bird population. After 2 hours. 65 of the striped and 23 of the red individuals were still alive. Use a chi-square test to assess the evidence that the mimic form survives more successfully. Use a directional alternative and let α = 0.05.
(a) State the null hypothesis in words.
(b) State the null hypothesis in symbols.
(c) Compute the sample survival proportions for each group and display the values in a table similar to Table 10.1.2.
(d) Find the value of the test statistic and the P-value.
(e) State the conclusion of the test in the context of this setting.