please can you solve it without excel?
The output voltage of a power supply is assumed to be normally distributed Ten observations taken at random on voltage are as follows. 11.25, 9.58, 11 54, 9.95, 10.28, 8.37, 10.44, 9.25, 9.38, and 10.85
a. Compute the mean, range, and standard deviation of the data set
b. Test the hypothesis that the mean voltage equals 12 V against a two-sided alternative using alpha = 0.05.
c. Construct a 95% two-sided confidence interval on n. What is your conclusion based on the confidence interval?