1. Gravetter/Wallnau Easentials-Chapter &-End-ef-chapter question 6 rardom sampl
ID: 3152117 • Letter: 1
Question
Explanation / Answer
3.
If n = 16:
Formulating the null and alternative hypotheses,
Ho: u = 30
Ha: u =/ 30
As we can see, this is a two tailed test.
Thus, getting the critical z, as alpha = 0.05 ,
alpha/2 = 0.025
zcrit = +/- 1.959963985
Getting the test statistic, as
X = sample mean = 33
uo = hypothesized mean = 30
n = sample size = 16
s = standard deviation = 8
Thus, z = (X - uo) * sqrt(n) / s = 1.5 [ANSWER]
Also, the p value is
p = 0.133614403
As |z| < 1.96, and P > 0.05, we FAIL TO REJECT THE NULL HYPOTHESIS.
You CANNOT conclude that the treatment has a significant effect. [ANSWER]
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If n = 64:
Formulating the null and alternative hypotheses,
Ho: u = 30
Ha: u =/ 30
As we can see, this is a two tailed test.
Thus, getting the critical z, as alpha = 0.05 ,
alpha/2 = 0.025
zcrit = +/- 1.959963985
Getting the test statistic, as
X = sample mean = 33
uo = hypothesized mean = 30
n = sample size = 64
s = standard deviation = 8
Thus, z = (X - uo) * sqrt(n) / s = 3 [ANSWER, Z]
Also, the p value is
p = 0.002699796
As |z| > 1.96, and P < 0.05, we FAIL TO REJECT THE NULL HYPOTHESIS.
You CAN conclude that the treatment has a significant effect. [ANSWER]
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Hence,
A larger sample INCREASES the likelihood of rejecting the null hypothesis. [ANSWER]
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