Tulips in the garden:pratice problem

The amount of tulips that blossom in Azia's tulip garden is normally distributed with a mean of 50 tulips and a standard deviation of 4. She tries a new fertilizer on a sample of 100 seeds and she is able to increase the amount of tulips that blossom by 16 percent, giving her 58 tulips. At a 5% confidence level does the new fertilizer really increase the amount of tulips that blossom. Use a hypothesis test.