Simplet-test and confidence intervall, population size???

#1
Hi everyone,

I want to determine the expected values for a certain test. Have I calculated correctly and used the correct test below? The data was collected doing random tests. I know the sample population is very small – can I still use this test if I assume that the data is normally distributed to get an indication on what values to expect if random tests are done?

X (mean) = 12.29
s2 (variance) = 0.058095
s (standard deviation) = 0.24103
N = 12.29
d.f (degrees of freedom) = 6
P (probability level) = 0.05 (95 %)
t value, two-tailed (from table) = (P=0.05/2=0.025 , d.f. = 6) = 2.45

X ± t×s/√N = 12,29 ± 2,45 × 0,24103/√7 = 12,29 ± 0,22 →[12,07 ;12,51] 95%

ie can expect (with a 95% confidence level) that the value will lie between 12.07 and 12.51

Thanks for any input,

Jonas