Effect of storage on a product. Does bread lose vitamins when stored? Researchers prepared four loaves of bread with flour fortified with a known amount of vitamins. After baking, they measured the vitamin C content of two loaves. The other two loaves were baked at the same time but were stored for three days and then measured for vitamin C content. The units are milligrams of vitamin C per hundred grams of flour (mg/100 g).

Here are the data:25 DATADATA DATADATADATA DATADATADATADATADATA DATADATADATADATADATA DATADATADATADATADATA DATADATADATADATADATA DATADATADATADATADATA DATADATADATADATADATA DATADATADATA DATADATADATADATADATA DATA FILE BREADVITC Immediately after baking: 47.62 49.79 Three days after baking: 21.25 22.34

(a) Does bread lose vitamin C when it is stored for three days?

Use a two-sample t test to answer this question. (State the hypotheses;

give the test statistic, degrees of freedom, and P-value;

and state your conclusion in nontechnical language.)

(b) Give a 90% confidence interval for the amount of vitamin C lost.