Question

Suppose that an independent research company was tasked with testing the validity of complaints against a pesticide manufacturing firm for under-filling their 20 lb bags of pesticide. Past experience has shown that the amount of pesticide dispensed by the machines that fill the bags follows a normal distribution with a mean of 20 lb and a standard deviation of 0.6 lb.

To verify the validity of the complaints, a researcher randomly selected 16 of the firm's 20 lb pesticide bags and recorded the following weights.

19.42,19.69,20.25,19.89,18.54,19.76,19.24,18.8,19.82,18.61,20.1,19.07,20.04,19.27,19.52,19.52

If you wish, you may download the data in your preferred format.  

CrunchIt!    CSV   Excel   JMP   Mac Text    Minitab   PC Text   R   SPSS   TI Calc  

The mean weight of the 16 bags collected was 19.471 lb. Calculate the value of the one-sample z‑ statistic.

Give your answer precise to three decimal places.

?=

Answer 1

Answer: Ho: M = 20 HA: u c20 n : sample size : 16 a = Sampie mean : 19.4711b C: Population SD = 0.6 SE : 015 Test statistic is ZCOC-ul 19.471- 20 SG 0:15 =-0.529 0.15 = -3.52666 ~ -3.527]