A truck company wants on-time delivery for 98% of the parts they order from a metal manufacturing plant. They have been ordering from Hudson Manufacturing but will Switch to a new, cheaper manufacturer (Steel-R-Us) unless there is evidence that this New manufacturer cannot meet the 98% on-time goal. As a test the truck company Purchases a random sample of metal parts from Steel-R-Us, and then determines if These parts were delivered on-time. Which hypotheses should they test? A) $\begin{array} { l } H _ { 0 } : p 0.98 \end{array}$ B) $\begin{array} { l } H _ { 0 } : p 0.98 \ H _ { a } : p = 0.98 \end{array}$ C) $\begin{array} { l } H _ { 0 } : p = 0.98 \ H _ { a } : p 0.98 \end{array}$

Question

A truck company wants on-time delivery for 98% of the parts they order from a metal manufacturing plant. They have been ordering from Hudson Manufacturing but will Switch to a new, cheaper manufacturer (Steel-R-Us) unless there is evidence that this New manufacturer cannot meet the 98% on-time goal. As a test the truck company Purchases a random sample of metal parts from Steel-R-Us, and then determines if These parts were delivered on-time. Which hypotheses should they test? A) $\begin{array} { l } H _ { 0 } : p < 0.98 \ H _ { a } : p > 0.98 \end{array}$ B) $\begin{array} { l } H _ { 0 } : p > 0.98 \ H _ { a } : p = 0.98 \end{array}$ C) $\begin{array} { l } H _ { 0 } : p = 0.98 \ H _ { a } : p < 0.98 \end{array}$ D) $\begin{array} { l } H _ { 0 } : p = 0.98 \ H _ { a } : p \neq 0.98 \end{array}$ E) $\begin{array} { l } H _ { 0 } : p = 0.98 \ H _ { a } : p > 0.98 \end{array}$

Quizplus · Accepted Answer

The truck company's goal is to have on-time delivery for 98% of the parts they order. Therefore, the null hypothesis should be that the true proportion of on-time deliveries from Steel-R-Us is 0.98. The alternative hypothesis should be that the true proportion is less than 0.98, as that would indicate that Steel-R-Us is not meeting the company's goal. Therefore, the correct set of hypotheses is:
H0: p = 0.98
Ha: p < 0.98

A Truck Company Wants On-Time Delivery for 98% of the Parts