Question 1
2 answers:
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Answer:
The critical value for this hypothesis test is 6.571.
Step-by-step explanation:
In this case the professor wants to determine whether the average number of minutes that a student needs to complete a statistics exam has a standard deviation that is less than 5.0 minutes.
Then the variance will be,
The hypothesis to determine whether the population variance is less than 25.0 minutes or not, is:
<em>H</em>₀: The population variance is not less than 25.0 minutes, i.e. <em>σ²</em> = 25.
<em>Hₐ</em>: The population variance is less than 25.0 minutes, i.e. <em>σ²</em> < 25.
The test statistics is:
The decision rule is:
If the calculated value of the test statistic is less than the critical value, then the null hypothesis will be rejected.
Compute the critical value as follows:
*Use a chi-square table.
Thus, the critical value for this hypothesis test is 6.571.
Answer:
Option D. 9 mi/hr downstream, 6 mi/hr upstream
Step-by-step explanation:
<u><em>The complete question is</em></u>
Alicia can row 6 miles downstream in the same time it takes her to row 4 miles upstream. She rows downstream 3 miles/hour faster than she rows upstream. Find Alicia’s rowing rate each way
Define the variables
Let
x -----> Alicia's rowing rate downstream in miles per hour
y ----> Alicia's rowing rate upstream in miles per hour
we know that
The rate is equal to the distance divided by the time
so
The time is equal to the distance divided by the rate
we have
-----> equation A
----> equation B
equate equation A and equation B
<em>Find the value of x</em>
therefore
Alicia's rowing rate downstream is 9 mi/h
Alicia's rowing rate upstream is 6 mi/h