The table represents the height of a rock that is dropped, h(t), in meters, after t seconds. (See picture.)
2 answers:
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Answer:
If we compare the p value and a significance level assumed we see that
so we can conclude that we reject the null hypothesis, and the actual true mean is higher than 210250 at 5% of significance.
Step-by-step explanation:
Data given and notation
represent the sample mean
represent the standard deviation for the sample
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 to be tested
We need to conduct a hypothesis in order to determine if the mean is higher than 210250, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
Compute the test statistic
We don't know the population deviation, so for this case is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:
(1)
t-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".
We can replace in formula (1) the info given like this:
Now we need to find the degrees of freedom for the t distirbution given by:
Conclusion
Since is a one right tailed test the p value would be:
If we compare the p value and a significance level assumed we see that
so we can conclude that we reject the null hypothesis, and the actual true mean is higher than 210250 at 5% of significance.
Answer:
The minimum score of those who received C's is 67.39.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
If 69.5 percent of the students received grades of C or better, what is the minimum score of those who received C's?
This is X when Z has a pvalue of 1-0.695 = 0.305. So it is X when Z = -0.51.
The minimum score of those who received C's is 67.39.