I have attached the question in the photo below. Both parts are important. Thank you.

The mean annual income of delivery workers in City X is $9,000 with a standard deviation of $900. You suspect that active union workers have higher average income. You take a random sample of 85 active union members, and find their mean income to be $9,200 and standard deviation, $1,000. (1) Do active union members have significantly higher incomes? (2) Explain your results