In order to construct a 95% confidence interval for the population mean when the population standard deviation is unknown and the sample size is 15, you should use the t-value indicated as: A) t_0.10,15 B) t_0.10,14 C) t_0.05,15 D) t_0.05,14 E) t_0.025,14

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When the population standard deviation is unknown and the sample size is small (n < 30), a t-distribution is used. For a 95% confidence interval, the two-tailed alpha level is 0.05, but since it's two-tailed, each tail has an alpha of 0.025. The degrees of freedom (df) for a sample size of 15 is n - 1 = 14. Therefore, the correct t-value notation is t0.025,14.

In Order to Construct a 95% Confidence Interval for the Population