x=c(7.6,9.6,10.4,10.7,11.9,14.1,14.6,18.5)
mean(x); sd(x)
[1] 12.175
[1] 3.434177
1 - pnorm(20, mean(x), sd(x))
[1] 0.01134643

t.test(x)

        One Sample t-test

data:  x
t = 10.027, df = 7, p-value = 2.101e-05
alternative hypothesis: true mean is not equal to 0
95 percent confidence interval:
  9.303956 15.046044
sample estimates:
mean of x
   12.175

sqrt(7*var(x)/qchisq(c(.975,.025), 7))
[1] 2.270589 6.989485

MTB > OneVariance 'x';
SUBC>   Confidence 95.0.

Test and CI for One Variance: x

Method

The chi-square method is only for the normal distribution.

Statistics

Variable  N  StDev  Variance
x         8   3.43      11.8

95% Confidence Interval

                         CI for        CI for
Variable  Method          StDev       Variance
x         Chi-Square  (2.27, 6.99)  (5.2, 48.9)