how would I Calculate z-score, when alpha is set to 0.5 should the null hypothesis be retained or rejected, explain why?

how would I Calculate z-score, when alpha is set to 0.5 should the null hypothesis be retained or rejected, explain why? Are the results statistically significant

Scenario: Lucy wants to know her fourth grade daughter, Monica, scored on a test of reading comprehension compared to the population of other fourth graders in the school district. Luckily Lucy has taken this course and knows that z-scores will help her understand Monica's reading score in relation to the population.

data as follows:

-Monica's reading comprehension score = 121

-Mean Fourth grade reading comprehension score = 147

• Standard Deviation of the fourth grade's reading comprehension = 14.8