The T Distribution and Degrees of Freedom Worksheet with Answer Key

What's on the worksheet

1. Each cell describes a random sample of size n from a normal population.
   n = 9; the t value with area 0.05 to its rightn = 16; the area to the right of t = 2.2n = 26; t^* for 95% confidencen = 5; the area to the left of t = -1.5n = 3; the area between −2 and 2
2. A naturalist times the gap between flashes for a random sample of 8 male fireflies of one species in a large meadow (made-up data).
3. A student times the crawling speed of a random sample of 6 garden snails on a glass sheet, in millimeters per second (made-up data).
4. Here is the row of a t table for df = 12.
5. For df > 2 the standard deviation of the t distribution is √(df)df - 2.
6. A printed t table has only these rows (two-sided confidence levels).
7. Say whether a z or a t critical value applies for a 95% interval for the mean, and why.