A group of retired people walks for an average of 300 seconds everyday. The walking activity follows the normal distribution. This group has been given an energy drink before start walking and result observed for a random sample of 15 retired people. These 15 people now walk for average of 310 seconds with a standard deviation of 8 seconds. Did the energy drink increase the average walking time?

(a)State the null hypothesis and the alternative hypothesis.

(b)Show the decision rule graphically. Use the 0.05 significance level.

(c ) Compute the value of t. What is your decision regarding the null hypothesis? Briefly summarize your results