Tamara bought a $22 mailbox using a 10% off coupon David bought an identical mailbox for $19.95 at a different store
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Answer:
If the observed sample mean is greater than 17.07 minutes, then we would reject the null hypothesis.
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 15 minutes
Sample size, n = 10
Alpha, α = 0.05
Population standard deviation, σ = 4 minutes
First, we design the null and the alternate hypothesis
Since the population standard deviation is given, we use one-tailed z test to perform this hypothesis.
Formula:
Now,
Thus, we would reject the null hypothesis if the z-statistic is greater than this critical value.
Thus, we can write:
Thus, the decision rule would be if the observed sample mean is greater than 17.07 minutes, then we would reject the null hypothesis.