Question

Q3: A nutritionist believes that 12-ounce boxes of cereal should contain an average of 1.2 ounces of bran. She suspects that a popular cereal has a different mean bran content. She carefully analyzes the contents of a random sample of twenty 12-ounce boxes of the cereal and finds that the mean bran content is 1.16 ounces. It is known that the standard deviation of the bran content of all such boxes of cereal is 0.08. Do the data provide sufficient evidence to conclude that the mean bran content of all 12-ounce boxes of this cereal differs from 1.2 ounces? Use a .05 level of significance.

Answer 1

given data are:-

sample mean() = 1.16

sample size (n) = 20

population sd() = 0.08

hypothesis:-

the test statistic be:-

the p value is :-

[ in any blank cell of excel type =NORMSDIST(-2.236)]

decision:-

p value = 0.0254 <0.05 (alpha)

so, we reject the null hypothesis.

We can say that, data provide sufficient evidence to conclude that the mean bran content of all 12-ounce boxes of this cereal differs from 1.2 ounces at 0.05 level of significance.

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