2) Consider the following hypothesis test:
H 0 : μ = 16
H a : μ ≠ 16
A sample of 50 provided a sample mean of 15.15. The population standard deviation is 3.
a) Compute the value of the test statistic.
b) What is the p-value?
c) Write the rejection rule using the p-value. Using α = 0.05, what is your conclusion?
d) Write the rejection rule using the critical value. What is your conclusion?
"H_0: \\mu = 16 \\\\\n\nH_1: \\mu \u2260 16 \\\\\n\nn = 50 \\\\\n\n\\bar{x} = 15.15 \\\\\n\n\\sigma = 3"
a)
Test-statistic
"Z = \\frac{\\bar{x} - \\mu}{\\sigma \/ \\sqrt{n}} \\\\\n\nZ = \\frac{15.15 -16}{3 \/ \\sqrt{50}} = -2.003"
b)
Two-tailed test.
P-value = 2P(Z< -2.003)
"= 2 \\times 0.0225 \\\\\n\n= 0.045"
The EXCEL formula to find the p-value for a two-tailed z-test is “=2*(NORM.S.DIST(-2.003, TRUE))”.
=0.045
c) α = 0.05
If the p-value is less than 0.05, we reject the null hypothesis.
0.045<0.05
Reject H0. Conclusion: "\\mu\\not = 16" at 0.05 level of significance.
d) α = 0.05
Reject H0 if Z ≤ -1.96 or Z ≥ 1.96
-2.003 < -1.96
Reject H0.
Conclusion: "\\mu \u2260 16" at 0.05 level of significance.
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