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Both standard deviations are known and we determined α 2 = 0.05. Now the degrees of...

Both standard deviations are known and we determined

α
2

= 0.05. Now the degrees of freedom needs to be found to find the corresponding t value from a table. The degrees of freedom is calculated as follows where s1 is the sample standard deviation for population 1, n1 is the sample size from population 1, s2 is the sample standard deviation for population 2, and n2 is the sample size from population 2.

df =

leftparen1.gif
s12
n1
+
s22
n2
rightparen1.gif 2
1
n1 − 1
leftparen1.gif
s12
n1
rightparen1.gif 2
+
1
n2 − 1
leftparen1.gif
s22
n2
rightparen1.gif 2

The needed values were found to be

n1 = 10,

s1 = 2.5634,

n2 = 8,

and

s2 = 3.5517.

Use these values to find the degrees of freedom, rounding the result to one decimal place.

math   Statistics-And-Probability   
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Homework Answers

Answer #1

Solution :

Given that standard deviations are known.

Degrees of freedom

= n1 + n2 - 2

= 10 + 8 - 2

= 16

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