Answer:
4
Step-by-step explanation:
The z-score is calculated by the following formula
z=(x-μ)/σ
where
μ=Population mean
σ=Population standard deviation
If the z-score for a specific sample mean is discussed then z-score is computed as
z=xbar-μ/σxbar.
where
μ=Population mean
σxbar=Sample standard deviation
As the population mean and mean of sampling distribution of mean are equal so, μ is used in above equation.
Now, the z-score is given
1.5=xbar-μ/σxbar
σxbar=xbar-μ/1.5.
Also we know that z-score corresponds to a score that is 6 points above mean which means that xbar-μ=6.
σxbar=6/1.5
σxbar=4.
Thus, the required sample standard deviation is 4.
