Use the following information for the next four questions. a city health department wishes to determine whether the mean bacteria count per unit volume of water at a lake beach is within the safety level of 200. a researcher collected ten water samples of unit volume and found the bacteria counts to be: 175, 190, 207, 193, 184, 204, 205, 193, 196, 180the sample mean of the observations is 192.7 and the sample standard deviation is 10.81. the bacteria counts are normally distributed. we want to test the null hypothesis that the mean bacterial count ( µ ) is 200 against the hypothesis that it is less than 200 (where there is no cause for concern).