Question

Maureen McIlvoy, owner and CEO of a mail order business for wind surfing equipment and supplies, is reviewing the order filling operations at her warehouses. Her goal is 100% of orders shipped within 24 hours. In previous years, neither warehouse has achieved the goal, but the East Coast Warehouse has consistently out-performed the West Coast Warehouse. Her staff randomly selected 200 orders from the West Coast Warehouse (population 1) and 400 orders from the East Coast Warehouse (population 2), and reports that 190 of the West Coast Orders were shipped within 24 hours, and the East Coast Warehouse shipped 356 orders within 24 hours. Assuming α = 0.05, the appropriate decision is ___________________. reject the null hypothesis p1 – p2 = 0 reject the null hypothesis μ1 - μ2 < 0 do not reject the null hypothesis μ1 - μ2 = 0 do not reject the null hypothesis p1 – p2 = 0 do not reject the null hypothesis p1 – p2 ≥ 0

Answer 1

We have to check whether proportion p1 is equal to p2 or not. So, it is a two tailed hypothesis

using TI 84 calculator

press stat then tests then 2-propZtest

enter the data

x1 = 190, n1 = 200, x2 = 356, n2 = 400

p1 not equal to p2

press calculate

we get

test statistic = 2.42  

p value = 0.0155

it is clear that the p value is less than significance level of 0.05, so we can reject the null hypothesis

reject the null hypothesis p1 – p2 = 0