Chicken Delight claims that 91% of its orders are delivered within 10 minutes of the time the order is placed. A sample of 90 orders revealed that 75 were delivered within the promised time. At the 0.10 significance level, can we conclude that less than 91% of the orders are delivered in less than 10 minutes?
What is the decision rule? (Reject Ho if z <)
Compute the value of the test statistic.