A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 433 gram setting

A manufacturer of chocolate chips would like to know whether its bag filling machine works correctly at the 433 gram setting. It is believed that the machine is underfilling the bags. A 26 bag sample had a mean of 427 grams with a standard deviation of 15. Assume the population is normally distributed. A level of significance of 0.05 will be used. Find the P-value of the test statistic.