A nutritionist is comparing the average daily calorie intake of two groups: vegetarians and non-vegetarians. A sample of $15$ vegetarians has a mean intake of $2,200$ calories with a standard deviation of $180$ calories, a sample of $20$ non-vegetarians has a mean intake of $2,500$ calories with a standard deviation of $210$ calories. At the $0.05$ significance level, what is the value of the test statistic for testing whether there is a significant difference in mean daily calorie intake between the vegetarian and non-vegetarian groups?

• A. $t=-2.54$
• B. $t=4.54$
• C. $t=-4.54$
• D. $t=-5.44$

Answer: (C)