Question

A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 400 gram setting. It is believed that the machine is underfilling the bags. A 9 bag sample had a mean of 397 grams with a standard deviation of 25. A level of significance of 0.025 will be used. Assume the population distribution is approximately normal. Determine the decision rule for rejecting the null hypothesis. Round your answer to three decimal places.

Answer 1

Reject
`H_o` if
`t < -2.306`

Explanation:

The decision rule for rejecting the null hypothesis is shown below:-

The machine is thought to be underfilling so that the test is left tailed.

Now the Degrees of freedom is

= 9 - 1

= 8

Critical left tailed value t for meaning level
`8 \ df` and 0.025 = -2.306

Therefore Decision rule will be in the following way:

Reject
`H_o` if
`t < -2.306`