Answer:
We conclude that speed is greater than 30 miles per hour.
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 30 miles per hour
Sample mean, = 35 miles per hour
Sample size, n = 15
Alpha, α = 0.01
Sample standard deviation, s = 4.7 miles per hour
First, we design the null and the alternate hypothesis
We use one-tailed(right) t test to perform this hypothesis.
Formula:
Putting all the values, we have
Now,
Since,
We fail to accept the null hypothesis and reject it. We accept the alternate hypothesis and conclude that speed is greater than 30 miles per hour.
We calculate the p-value.
P-value = 0.00052
Since p value is lower than the significance level, we reject the null hypothesis and accept the alternate hypothesis. We conclude that speed is greater than 30 miles per hour.