Question

A machine at ATM & Co. fills 120-ounce jugs with laundry softner. a quality control inspector wishes to test if the matchine underfills the jugs or not. Assume the distribution of the amount of laundry softner in these jugs is normal under standard cicumtance, the mean amount should be 120 ounces with a standard deviation of 1 ounce.

a. what are the hypothesis the quality control inspector wishes to test?

b. Suppose the quality control inspector wishes to conduct the test using alpha=0.10 and a sample size of 40 . what is the range of values of xbar for whice he will accept H0?

C. suppose the quality control insppector wishes to conduct the test using alpha=0.1 and a sample size of 40. if the true mean amount of deter

Answer 1

hypothesis

H0: u=120

H1: u<120

Explanation:

a. let u=mean amount of laundry softener in 120-ounce jugs

hypothesis

H0: u=120

H1: u<120

b.

we have level of significance α =0.01

we know that left tailed critical z value =-2.33

n=40

since

z=(x-u)/(σ/n​ )

so

-2.33=(x-120)/(1/40​ )

or

x=105.26 ounces

range of values

=0 to 105.26 ounces