Solve the below problem:
Q: A manufacturer claims that 20% of the population in the city preferred her product. A sample of 100 persons is taken to check her claim. It is found that 8 of these 100 persons preferred her product over other products available in the market.
a. Find the p-value of the test (use a two-tailed test).
b. Using the 0.05 level of significance test her claim