Identify the test statistics to be used in the following statement below.

The bakers said that the mean weight of their banana cake is 300 grams. To check if it is true, the bakers selected a random sample of 40 banana cakes and used hypothesis testing to investigate. Determine what test statistic is appropriate for the situations. 1. The population standard deviation is known to be 10 grams and the sample size used is 40 with a mean weight of 290 grams. 2. The sample size is reduced to 25 which in turn changed the mean and standard deviation to 290 grams and 25 grams, respectively