4) The percentages of acetic acid in five vinegar samples were 4.98, 4.86, 4.97, 4.99. 5.08, 5.11, 4.97, 5.32 and 4.89. Could we reject any of these values with 95% confidence?

5) A new procedure for the determination of mercury (Hg) was analyzed in samples with a preparation method that contained 0.213%. My% Hg results were 0.222%, 0.218%, 0.215%, 0.216%, and 0.229%. Is there a significant systematic error at the 95% and 99% confidence level?

6) The homogeneity of a standard chloride sample was evaluated by analyzing portions of the material taken from the surface and bottom of the container, the results obtained were as follows:

Percent Chloride

Surface. Background

26.32 26.28

26.33 26.25

26.38 26.38

26.39

The standard deviation of the 7 samples is 0.054%. Can the homogeneity of the material be demonstrated with a confidence level of 90% and 95%?

7) Calculate the 95% confidence limit for the average value of 1.67ppm of three samples of mercury that according to previous experience it is known that s = 0.10ppm of Hg.