MHB Establish Whether populations have equal variance

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To determine if the populations from day 1 and day 2 have equal variances at the 0.05 significance level, the F-test is recommended. The F-test statistic is calculated using the formula F = s1²/s2², where s1² is the larger variance. After calculating the F-value, it is necessary to compare it against a critical value from an F-table based on the degrees of freedom. If the calculated F-value exceeds the critical value, the variances are considered different; if not, they are assumed equal. Understanding these steps is crucial for correctly applying the F-test to the given data.
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day 1
distance equals 52.175m, std = 0.015m and n = 10

day 2
distance equals 52.193m, std = 0.021m and n = 11

Establish whether the two populations have equal variance at the 0.05 signifcance level. Can someone help me out with how to get to the answer and what the answer actually is?
 
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Wrightomatic said:
day 1
distance equals 52.175m, std = 0.015m and n = 10

day 2
distance equals 52.193m, std = 0.021m and n = 11

Establish whether the two populations have equal variance at the 0.05 signifcance level. Can someone help me out with how to get to the answer and what the answer actually is?

Welcome to MHB, Wrightomatic! :)

The F-test is the appropriate test to compare variances.
Do you know how to execute it?
 
No sorry i don't know how that is why I am asking. Could you please demonstrate how to apply such a test for the given data?

Thanks for your help :)
 
Wrightomatic said:
No sorry i don't know how that is why I am asking. Could you please demonstrate how to apply such a test for the given data?

Thanks for your help :)

The F-test statistic is $F=\dfrac{s_1^2}{s_2^2}$, where $s_1^2$ is the larger of the 2 variances.
Can you calculate that?
 
Yes I can calculate that but what does the F test mean? Like ill get the value for F then do i need to do anything else. As you can probably tell I have absolutely no idea how to do the test or how to implement it.

Could you possibly give me all the steps/formulas i will need and then I can work through it and check the final answer with you?
 
Wrightomatic said:
Yes I can calculate that but what does the F test mean? Like ill get the value for F then do i need to do anything else. As you can probably tell I have absolutely no idea how to do the test or how to implement it.

Could you possibly give me all the steps/formulas i will need and then I can work through it and check the final answer with you?

Well, you can find the steps/formulas for instance here.

The F-test tests if 2 variances are different.
You should look up the critical value in an F-table for the appropriate significance and degrees of freedom (see the article).
If your calculated F-value is greater than this critical value, your variances are different.
If it is lower, the variances are assumed equal.
 
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