Final answer:
The critical value used for a 95% confidence interval with a sample size of 28 is based on the t-distribution and the degrees of freedom, which would be 27. The correct t-score rounded to three decimal places would be 2.048, option (c).
Step-by-step explanation:
When calculating a 95% confidence interval with a sample size of 28, the critical value is based on the t-distribution since the sample size is small (n < 30). The degrees of freedom (df) for this study would be 27 (sample size - 1). Using a t-distribution table or an appropriate calculator, you would find the t-score that corresponds to the 95% confidence level and 27 degrees of freedom.
The given options do not include t-scores, so you would typically need to consult a t-distribution table or calculator to obtain the precise t-score for 27 degrees of freedom at 95% confidence level.
However, among the provided options, the correct choice is (c) 2.048 which is the t-score close to the 95% confidence interval t-value for 27 degrees of freedom, rounded to three decimal places.