In: Statistics and Probability
A meteorologist who sampled 13 randomly selected thunderstorms found that the average speed at which they traveled across a certain state was 1.7 miles per hour. The standard deviation of the sample was 1.7 mph. Find the 99% confidence interval of the mean. Do not round the t value from the table. Round the t-interval to one decimal place, example 1.2 < μ < 3.4
T value from the table for the formula:
T-interval: < μ <
The provided sample mean is = 1.7 and the sample standard deviation is s = 1.7. The size of the sample is n = 13 and the required confidence level is 99%.
The degrees of freedom is df=13−1=12, and the significance level is α=0.01.
T value from the table is tc = 3.055.
The 99% confidence for the population mean μ is computed using the following expression
CI = (1.7−1.44,1.7+1.44) = (0.26,3.14) (0.3, 3.1)
T-interval: 0.3 < < 3.1