What is the answer? please
2 answers:
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Answer:
If we compare the p value and the significance level given we see that
so we can conclude that we FAIL to reject the null hypothesis, and the the actual mean is not significant different from 70.
Explanation:
1) Data given and notation
represent the sample mean
represent the standard deviation for the population
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
t would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
State the null and alternative hypotheses.
We need to conduct a hypothesis in order to determine if the mean is different from 70, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
We know the population deviation, so for this case is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:
(1)
z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".
Calculate the statistic
We can replace in formula (1) the info given like this:
Calculate the P-value
First we need to calculate the degrees of freedom given by:
Since is a two tailed test the p value would be:
Conclusion
If we compare the p value and the significance level given we see that
so we can conclude that we FAIL to reject the null hypothesis, and the the actual mean is not significant different from 70.
Answer: 15.87 m
From the equation of motion:
where, is the distance traveled,
is the initial velocity,
is the acceleration and
is the time.
The rock free falls under gravity. Initial velocity, ,
It took for rock to hit the water.
Substitute the values in the given equation:
Hence, the water is 15.87 m below the top level of the well.