Respuesta :
The mean and the standard deviation of the sampling distribution of x⁻₁ - x⁻₂ are respectively; 15, √[(4²/100)+ (7²/85)]
Sampling Distribution
We are given;
For Population 1;
- Mean; x⁻₁ = 40
- Standard deviation; σ₁ = 4
- Sample size; n₁ = 100
For Population 2;
- Mean; x⁻₂ = 25
- Standard Deviation; σ₂ = 7
- Sample size; n₂ = 85
Thus, the mean of the sampling distribution is;
x⁻₁ - x⁻₂ = 40 - 25
x⁻₁ - x⁻₂ = 15
Now, the formula for the standard deviation of the sampling distribution is; s = √[(σ₁²/n₁) + (σ₂²/n₂)]
Thus;
s = √[(4²/100)+ (7²/85)]
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