SOLUTION: In Country A, the population mean height for 3-year old boys is 39 inches. Suppose a random sample of 15 3-year old boys from Country B showed a sample mean of 38.8 inches with a s

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Question 933923: In Country A, the population mean height for 3-year old boys is 39 inches. Suppose a random sample of 15 3-year old boys from Country B showed a sample mean of 38.8 inches with a standard deviation of 2 inches. The boys were independently sampled. Assume that heights are Normally distributed in the population.
A. Determine whether the population mean for Country B boys is significantly different from the Country A mean. Use a significance level of 0.05.
Which of the following correctly states H0 and Ha?
A. H0: u = 39
Ha: u<39
B. H0: u less than or equal to 39
Ha: u <39
C. H0: u = 39
Ha: u >39
D. H0: u = 39
Ha: u does not equal 39
E. H0: u does not equal 39
Ha: u = 39
F. H0: u > 39
Ha: u is less than or equal to 30
Find the test statistic
t= (type an integer or decimal rounded to two decimal places as needed)
Find the p-value
p = (type an integer or decimal rounded to two decimal places as needed)
Reject or do not reject H0?
Thank you
Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website!
H0: u = 39
Ha: u<39
......
Sample of 15 Statistics: mean of 38.8", standard deviation = 2 inches
....
test stat: z = -.2/(2/sqrt(15)) = -.39 rounded
p(z < -.39) = .35 rounded
......
significance level of 0.05. (critical value z = -1.64 rounded)
.......
.35 > .05
Do not reject Ho.
......
For the normal distribution: Below: z = 0, z = � 1, z= �2 , z= �3 are plotted.
.35 the Area under the standard normal curve to the left of z = -.39
Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50% to the right