The temperature readings for a sample of 25 fall days (degrees Celsius) in Winnipeg, Manitoba, have a mean of 10 degrees and a standard deviation of 5 degrees. Assuming the temperatures are normally distributed, a 95% confidence interval estimate for the fall true mean temperature is: a. (7.940, 12.060) b. (8.355, 11.645) c. None of the choices are true. d. (7.936, 12.064) e. (8.040, 11.960)