it says you have to understand the tTest please helpSolution

it says you have to understand the t-Test. please help

Null Hypothesis : Mean = 250

Alternate Hypothesis : Mean != 250

Mean = 250

n =15

Sample X-bar = 267

Standard Deviation = 12.1

z = (X-bar - Mean) / (SD/sqrt(n))

= (267 - 250)/(12.1/sqrt(15))

= 5.44

Therefore P-vale = 1 - (0.99998) ~ 0

Since, P < 0.05,

We will reject the null hypothesis.