What formula do I use to solve: A sample with a mean of M = 40 and a variance of s2 = 20 has an estimated standard error of 2 points. How many scores are in the sample?
standard error = s/√n
Note: The square root of the variance is called the Standard Deviation
With your data:
2 = (4.472)/√n
Solve for n.
I hope this is what you were asking.
To solve for the number of scores in the sample, you can use the formula for the standard error:
Standard Error (SE) = √(population variance / sample size)
In this case, the estimated standard error (SE) is 2 points, and the population variance (s^2) is 20. Plugging in these values into the formula, we get:
2 = √(20 / sample size)
To solve for the sample size, we can square both sides of the equation:
2^2 = (√(20 / sample size))^2
4 = 20 / sample size
Next, we can rearrange the equation to solve for the sample size:
sample size = 20 / 4
sample size = 5
Therefore, there are 5 scores in the sample.
To estimate the number of scores in the sample, we can use the formula for calculating the standard error of the mean (SEM).
The formula for the standard error of the mean is:
SEM = sqrt(s^2/n)
where SEM is the estimated standard error of the mean, s^2 is the sample variance, and n is the sample size.
Given that SEM = 2 and s^2 = 20, we can rearrange the formula to solve for n:
2 = sqrt(20/n)
Now, let's solve for n step by step:
Square both sides of the equation to eliminate the square root sign:
4 = 20/n
Rearrange the equation to solve for n:
n = 20/4
Simplify the equation:
n = 5
Therefore, there are 5 scores in the sample.