Answer :
Answer:
Step-by-step explanation:
a. To identify the alternative hypothesis, we have to examine the claim
The claim is that the mean nickel diameter drawn by children in the low income group is greater than 21.21 mm
Thus, alternative hypothesis is μ > 21.21
b. The test statistics is
z score = x - u /(sd/√n)
Where x (sample mean) is 23.375, u is pop. mean is 21.21, sd is 5.29 and n (sample size) is 40
z = 23.375 - 21.21 /(5.29/√40)
z = 2.165 / (5.29/6.3246)
z = 2.165/0.8364
z = 2.588
c. The critical value is
Alpha for this case study is 0.01. Then the critical probability is 1 - (alpha/2) =
1 - (0.01/2) = 1 - 0.005 = 0.995
To express the critical value as a z score, find the z score corresponding to the critical probability using the z table. Which is 0.8389.