Question

Hi,

I am having some difficulty with the following questions, especially with the significance levels. Would anyone be able to lend a hand?

http://i.imgur.com/lofkz.png

Thanks very much :)

Answer 1

it does not open

Answer 2

An article in Food Testing and Analysis (“Improving Reproducibility of Refractometry Measurements of Fruit Juices” Vol.4, No.4, pp13–17) reported the results
of a study that measured the sugar concentration (Brix) in clear apple juice. All
readings were taken at 20 degrees C.

11.48 11.45 11.48 11.47 11.48
11.50 11.42 11.49 11.45 11.44
11.45 11.47 11.46 11.47 11.43
11.50 11.49 11.45 11.46 11.47

(a) Test, at the 5% level of significance, whether the sugar concentrations
follow a normal distribution.
(b) Test, at the 5% level of significance, whether the mean sugar concentration
is 11.5 Brix.
(c) Find a 95% confidence interval for mean sugar concentration.
(d) How does the confidence interval found in part (c) confirm the conclusion
reached on the basis of the test in part (b)?