Chapter 21, Problem 16E

Friday the 13th, accidents The researchers in Exercise 15 also examined the number of people admitted to emergency rooms for vehicular accidents on 12 Friday evenings (6 each on the 6th and 13th).

Based on these data, is there evidence that more people are admitted, on average, on Friday the 13th? Here are two possible analyses of the data:

Paired t-Test of μ(1 – 2) = 0 vs. μ (1 – 2) < 0

Mean of Paired Differences = –3.333

t-Statistic = –2.7116 with 5 df

P = 0.0211

2-Sample t-Test of μ1 = μ2 vs. μ1 < μ2

Difference Between Means = –3.333

t-Statistic = –1.6644 with 9.940 df

P = 0.0636

1. a) Which of these tests is appropriate for these data? Explain.
2. b) Using the test you selected, state your conclusion.
3. c) Are the assumptions and conditions for inference met?