Question

A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 438 gram setting. It is believed that the machine is underfilling the bags. A 21 bag sample had a mean of 435 grams with a standard deviation of 25. Assume the population is normally distributed. A level of significance of 0.02 will be used. Specify the type of hypothesis test.

a. Left-Tailed Test
b. Right-Tailed Test
c. Two-Tailed Test

Answer 1

Answer: a. Left-Tailed Test

Explanation:

The type of hypothesis test is depended on the alternative hypothesis for the objective made by the researcher .

By considering the given information,

The objective for the study : Whether machine is filling 438 grams or under filling.

i.e. either
`\mu=438` or
`\mu<438` , where
`\mu` is the population mean .

Since alternative hypothesis consist "<" sign.

So our alternative hypothesis here =
`H_a:\mu<438`

Since the alternative hypothesis is left -tailed [tail is on left -side] , it means we have to perform a Left-Tailed Test.

Hence, the correct answer is a. Left-Tailed Test .