A school has two kindergarten classes. There are 21 children in Ms. Toodle's kindergarten class. Of these, 17 are "pre-readers" children on the verge of reading. There are 19 children in Mr. Grimace's kindergarten class. Of these, 13 are pre-readers. Using the plus four confidence interval method, a 90% confidence interval for the difference in proportions of children in these classes that are pre-readers is -0.104 to 0.336.
1. Which of the following statements is correct?
a. This confidence interval is not reliable because the samples are so small.
b. This confidence interval is of no use because it contains 0, the value of no difference between classes.
c. This confidence interal is reasonable because the sample sizes are both at least 5.
d. This confidence interval is not reliable because these samples cannot be viewed as simple random samples taken from a larger population