To compare the effect of weather on sales of soft drinks, a soda manufacturer sampled two regions of the country with the following results. Is there a difference in sales between the 2 regions? i. The alternate hypothesis is p_a- p_b$\neq$ 0. ii. The pooled estimate of the population proportion is 0.36. iii. Using the 1% level of significance, the critical value is $\pm$1.96. A) (i), (ii), and (iii) are all correct statements. B) (i) and (ii) are correct statements but not (iii). C) (i) and (iii) are correct statements but not (ii). D) (ii) and (iii) are correct statements but not (i). E) (ii) is a correct statement but not (i) and (iii).

Question

Quizplus · Accepted Answer

(i) is a correct statement because it presents the alternate hypothesis that there is a difference in sales between the two regions. 
(ii) is a correct statement because it provides the pooled estimate of the population proportion. 
(iii) is not entirely correct. The critical value for a two-tailed test at a 1% level of significance is ±2.576, not ±1.96 as given. However, since the alternate hypothesis in (i) is not a two-tailed test but a one-tailed test, we only need to consider the critical value for a one-tailed test at a 1% level of significance, which is 2.326. Thus, (iii) is not correct in terms of the specific critical value given but the correct critical value for the one-tailed test is within the range of the given critical value. Therefore, the best answer is (B).

To Compare the Effect of Weather on Sales of Soft ≠\neq=

To Compare the Effect of Weather on Sales of Soft $\neq$