Step-by-step explanation:
a. The mean can be found using the AVERAGE() function.
x = 272.7
b. The standard deviation can be found with the STDEV() function.
s = 39.9
c. The t-score can be found with the T.INV.2T() function. The confidence level is 0.04, and the degrees of freedom is 26.
t = 2.162
d. Find the lower and upper ends of the confidence interval.
Lower = 272.7 − 2.162 × 39.9 = 186.5
Upper = 272.7 + 2.162 × 39.9 = 358.9
