Question 874760
(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)  are the Smaller and larger Critical Values. In addition, just in case you need the p-value for 2 tails it would be 0.062 and for one tail it would be 0.031.  You can used the Free p-value online calculator to calculate these additional values and double check that they are correct.