1. Do students tend to improve their SAT Mathematics (SAT-M) score the second time they take the test? A random sample of four students who took the test twice received the following scores:
Assume that the change in SAT-M score (second score - first score) for the population of all students taking the test twice is Normally distributed with mean μ. A 95% confidence interval for μ is
A. 25.0 ± 64.29.
B. 25.0 ± 56.09.
C. 25.0 ± 39.60.
2. The one-sample t statistic from a sample of n = 19 observations for the two-sided test of
H0: μ = 6
Ha: μ ≠ 6
has the value t = 1.93. Based on this information
A. we would reject the null hypothesis at α = 0.10.
B. 0.025 < P-value < 0.05.
C. Both choices are correct.
3. You are thinking of using a t procedure to construct a 95% confidence interval for the mean of a population. You suspect the distribution of the population is not Normal and may be skewed. Which of the following statements is correct?
A. You should not use the t procedure since the population does not have a Normal distribution.
B. You may use the t procedure provided your sample size is large, say at least 50.
C. You may use the t procedure since it is robust to nonnormality.