Answer:
The sample standard deviation of the 14 measurements is 3.93
Step-by-step explanation:
The standard deviation = √(variance)
The standard deviation is the square root of variance. And variance is an average of the squared deviations from the mean.
Mathematically,
Standard deviation = σ = √[Σ(x - xbar)²/N]
x = each variable
xbar = mean
N = number of variables
For 12 variables,
N = 12
σ = 4.25
xbar = 38
Σ(x - xbar)² = sum of the square of all deviations; let it be equal to D
4.25 = √[Σ(x - xbar)²/12]
4.25 =√(D/12)
4.25² = D/12
D = 216.75.
For 14 measurements,
N = 14
The mean is going to still be 38, because the two new measurements are each 38.
xbar = 38
And the new additions to the sum of deviations, will be (38 - 38)² twice, that is, 0.
Standard deviation for 14 measurements
Standard deviation = σ = √[Σ(x - xbar)²/N]
σ = √(216.75/14) = 3.93
