An Analyst Is Assigned a Blind Quality Control Sample of Blood

Multiple Choice

An analyst is assigned a blind quality control sample of blood containing a drug metabolite. He tests ten separate portions and obtains the following data for the concentration in ug/mL:
25.2
24.8
26.6
27.0
24.0
26.0
25.5
26.3
24.9
23.9
The student t value for 10 samples, nine degrees of freedom is 2.262. Using the sample standard deviation for this data set, what is the ± value of the 95% confidence interval? Report to two decimal places

A) 0.72
B) 0.80
C) 0.76
D) 0.62