[单选题]

Use the following values from a student's t-distribution to establish a 95% confidence interval for the opulation mean given a sample size of 10, a sample mean of 6.25, and a sample standard eviation of 12. Assume that the population from which the sample is drawn is normally distributed and the population variance is not known.

The 95% confidence interval is closest to a:

A.Lower bound of -0.71 and an upper bound of 13.21.

B.Lower bound of -2.20 and an upper bound of 14.70.

C.Lower bound of -2.33 and an upper bound of 14.83.

参考答案与解析: