The lift force on a Wortmann airfoil is measured five times

The lift force on a Wortmann airfoil is measured five times under the same experimental conditions. The acquired values are 10.5 N, 9.4 N, 9.1 N, 11.3 N, and 9.7 N. Assuming that the only uncertainty in the experiment is a temporal random error as manifested by the spread of the data, determine the uncertainty in N at the 95% confidence level of the true mean value of the lift force.

Solution

Getting the mean and standard deviaiton of this data,

X = 10
s = 0.894427191

Here,

df = n - 1 = 5 -1 = 4

Thus, for 95% confidence, the t value is

t = 2.776445105

Thus,

E (margin of error) = t s / sqrt(n) = 2.776445105*0.894427191 / sqrt(5)

E = 1.110578042 [answer]