The GPA of sample of students in UCCB has sample mean 3.9106 and sample standard deviation 0.256, with 95% confidence interval (3.488,4.333). Which of the following is right?
a. If we sample many times, the proportion of intervals calculated that cover the true mean is regarding 95%.
b. There's a 95% chance that true mean falls between 3.488 and 4.333.
c. The estimate is in 95% of true mean.
d. The population has normal distribution with the mean 3.9106 as well as standard deviation 0.256.