Question

g A coffee-dispensing machine is supposed to deliver eight ounces of liquid into each paper cup, but a consumer believes that the actual mean amount is less. The critical value for z for a one-tailed test with the tail in the left end is minus1.645 and the obtained value is minus1.87. The appropriate decision is ________.

Answer 1

Answer: Reject the eight- ounces claim.

Step-by-step explanation:

For left tailed test , On a normal curve the rejection area lies on the left side of the critical value.

It means that if the observed z-value is less than the critical value then it will fall into the rejection region other wise not.

As per given ,

Objective : A coffee-dispensing machine is supposed to deliver eight ounces of liquid or less.

Then ,

$H_0: \mu=8\\\\H_a: \mu<8$ , since alternative hypothesis is left-tailed thus the test is an left-tailed test.

the critical value for z for a one-tailed test with the tail in the left end is -1.645 and the obtained value is -1.87.

Clearly , -1.87 < -1.645

⇒ -1.87 falls under rejection region.

⇒  Decision : Reject null hypothesis.

i.e. we reject the eight- ounces claim.