Question

. Average coffee consumption among graduate students is commonly known to be 3.89 cups per day. A graduate student took a sample of 10 fellow graduate students in her statistics class, and in the sample produced a mean of 4.02 cups per day and a standard deviation of .19. Because of this, she believes that the average is actually greater than what is commonly thought (3.89 cups per day). Do we believe the graduate student’s claim or the common belief? Use a significance level of .01. Show all the steps (4 steps)

Answer 1

Steps 1) Ho : mean = 3.89 H: mean= 4.02

2) alpha = 0.01 (given) Test static Zo formula is mentioned. On solving Zo = 2.164

3) For alpha =0.01   Zalpha = 2.33 (from Z Table)

4) Zo < Zalpha , ie, 2.164 < 2.33 ,As Zo < Zalpha & the null hypothesis Ho is accepted at 1% significance level and we can conclude that the common belief is true.

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