What does the 2 represent in the number 52.3

How do i make someone brainliest? (if you answer me, i might be able to make you brainliest! )

The weight of full–grown tomatoes at a farm is modeled by a normal distribution with a standard deviation of 18.4 grams. the 95 percent confidence interval for the mean weight of the tomatoes is calculated using a sample of 100 tomatoes. what is the margin of error (half the width of the confidence interval)?

When y’all answer can y’all explain too !