pls answer

1. Determine the t-value {tabular value} when n = 12 and a: = 0.05. 2. Find the t-value (computed value] of the given sample means: p = 13, Tc: 15, n = 10, s = 1.3. 3. An electronic company claims that the average life of the smartphone battery it manufactures is 20 hours with a standard deviation of 4 hours. What is the tvalue if a random sample of 25 smartphones chosen has a sample mean of 18 hours? 4. Calculate the 85th percentile from the value of the lower cumulative distribution of the student's t- distribution when the sampie size is 10? 5. Find the t-values that bound the middle 50% with df= 14