Question 783977
(X ̅-μ)/(σ/√n)=>Standard Error=σ/√n=(24.27)/√25=4.854; 
Thus using (X ̅-μ)/E  would be the new formula to use (±1509.5-1500)/(4.854)=>(±9.5)/(4.854)≈ 
(-1.957 and 1.957) this gives you the t-values not the critical values. 
In addition, the p-value for 2 tails would be 0.062.  Using the free p-value online calculator. On the TI 83/84 calculator enter 2nd distr number 5 tcdf(1.957, 1000, 24) = 0.031*2=0.062 > 0.05 

Critical value pertaining to this test is found in Table F, t-distribution table, at 24 degrees of freedom, 0.05, and 2 tails you find that the values will be between -2.093 < 2.093 thus TI83/84 will show the p-value of 0.05 such that 2nd distr, number 5 tcdf(2.093, 1000, 24)=0.0250*2 = 0.050 which relates to the original hypothesis in the question.