A recent survey indicated that the average amount spent for breakfast by business managers was $7.58,
with a standard deviation of $0.42. It was felt that breakfasts on the West Coast were higher than $7.58. A
sample of 81 business managers on the West Coast had an average breakfast cost of $7.65.
-At $a = 0.05$ , what is the test value?
A) 1.96
B) 1.5
C) -1.5
D) 1.64

Question

Quizplus · Accepted Answer

The test value is calculated using the formula for the z-test: $ z = \frac{\bar{x} - \mu}{\sigma/\sqrt{n}} $. Here, $\bar{x} = 7.65$, $\mu = 7.58$, $\sigma = 0.42$, and $n = 81$. Plugging in these values gives $ z = \frac{7.65 - 7.58}{0.42/\sqrt{81}} = 1.5 $.

A Recent Survey Indicated That the Average Amount Spent for Breakfast