In: Statistics and Probability
Use the t-distribution and the sample results to
complete the test of the hypotheses. Use a 5% significance level.
Assume the results come from a random sample, and if the sample
size is small, assume the underlying distribution is relatively
normal.
Test H0 : μ=100 vs Ha : μ<100 using the sample results x¯=91.7,
s=12.5, with n=30.
Ho : µ = 100
Ha : µ < 100
(Left tail test)
Level of Significance , α =
0.05
sample std dev , s = 12.5000
Sample Size , n = 30
Sample Mean, x̅ = 91.7000
degree of freedom= DF=n-1= 29
Standard Error , SE = s/√n = 12.5000 / √
30 = 2.2822
t-test statistic= (x̅ - µ )/SE = (
91.700 - 100 ) /
2.2822 = -3.64
p-Value = 0.0005 [Excel
formula =t.dist(t-stat,df) ]
Decision: p-value<α, Reject null hypothesis
..........
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