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You wish to compare the prices of apartments in two neighboring towns. You take a simple random sample of 12 apartments in town A and calculate the average price of these apartments. You repeat this for 15 apartments in town B. Let μ1 represent the true average price of apartments in town A and μ2 the average price in town B. If we were to use the pooled t test, what would be the degrees of freedom?

Respuesta :

akiran007

Answer:

Ï…= 25

Step-by-step explanation:

IF we have two small independent samples from two normal populations with means  μ1 and μ2 and standard deviations σ1 and σ 2   but unknown ,then the unbiased pooled or combined estimate of the common variance sigma square ha s student's t distribution with  degrees of freedom given by

Ï…= n1+ n2- 2

In the given question

Sample  A size= n1= 12

Sample B size = n2= 15

υ=  12+15-2

Ï…= 25

where

sp²= (n1-1) s1² + (n2-1) s2² / n1+n2-2

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