4. A surveying team needs to measure the distance across the lake. They make the measurements shown along the ground. What is th
1 answer:
Applying the Law of Cosines, the distance across the lake is: 2.1 miles.
<h3>What is the Law of Cosines?</h3>Law of Cosines is given as: c² = a² + b² - 2(a)(b)cos(C).
The diagram showing the measurements along the ground is in the attachment below.
Given:
- a = 2.82 miles
- b = 3.11 miles
- C = 40.3°
- c = distance across the lake.
Applying the Law of Cosines, we have:
c² = 2.82² + 3.11² - 2(2.82)(3.11)cos(40.3)
c² = 4.25
c = √4.25
c = 2.1 miles
Thus, applying the Law of Cosines, the distance across the lake is: 2.1 miles.
Learn more about Law of Cosines on:
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Answer:
Null hypothesis:
Alternative hypothesis:
Step-by-step explanation:
1) Data given and notation
represent the sample mean
represent the population standard deviation
sample size
represent the value that we want to test
represent the significance level for the hypothesis test.
z would represent the statistic (variable of interest)
represent the p value for the test (variable of interest)
2) State the null and alternative hypotheses.
We need to conduct a hypothesis in order to check if the mean is higher than 8000, the system of hypothesis are :
Null hypothesis:
Alternative hypothesis:
Since we know the population deviation, 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".
3) Calculate the statistic
We can replace in formula (1) the info given like this:
4) P-value
Since is a one-side upper test the p value would given by:
5) Conclusion
If we compare the p value and the significance level assumed, for example we see that
so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the mean is significantly higher than $8000.