HW: 12.1 Testing Goodness of Fit Assignment

Can someone explain, step by step how to get this answer, please?

*note: If you can show equations it would be helpful for me to be able to follow.

7. Following are observed frequencies for five categories: Category 1 2 3 45 Observed 25 14 23 6 2 a. Compute the expected frequencies for testing Ho: : p1 = 0.3, p2 = 0.25, p3 = 0.2, p4 = 0.15, p5 = 0.1. Answer 2 3 4 5 21.0 17.5 14.0 10.5 7.0