A phone company claims that their phone battery can last more than a day (24 hours) without charging. To test this claim, Robert collected a random sample of 25 phones and recorded how much time each phone can last without charging. The sample mean is 25 hours and the sample standard deviation is 2.5 hours. What is the distribution of the test statistic under the null hypothesis? normal distribution with mean 0 and variance 1 normal distribution with mean 24 and standard deviation 25 normal distribution with mean 24 and standard deviation 0.5 Ostudent t distribution with 24 dagrces of freedom student t distribution with 25 degrees of freedom