Q1. Suppose you form a confidence interval for a sample average and the population standard deviation is known. What happens to the width of the confidence interval as the sample size (n) increases?
A. Becomes wider
B. Becomes narrower
C. Width does not change
Q2. You want to form a margin of error for your company's monthly average sales estimate, and you do not know the population standard deviation for the sales variable. Which statistical table do you use to compute the margin of error?
A. Standard normal distribution
B. F distribution
C. Student's t distribution
Q3. You work in market analysis for a retail clothing store, and your team surveyed past customers to estimate the mean annual income per client. Suppose you want to test the null hypothesis that the population mean annual income is less than or equal to $60,000, and the alternative hypothesis states that the population mean is greater than $60,000. Is the critical value for making the test decision a positive or negative number?
A. Critical value is positive
B. Critical value is negative
C. Critical value is zero
D. We do not have enough information to answer this question
Q4. Suppose you are conducting a one-sided t-test, and the critical value for the test is 2.374. What happens to the critical value if you decrease the probability of a Type I error (alpha)?
A. Critical value remains unchanged
B. Critical value increases
C. Critical value declines
Q5. When do we use matched-pair differences to test hypotheses about population means?
A. The sizes of the two samples are unequal
B. The variances of the two samples are the same
C. The two samples are dependent
D. The variances of the two samples are unknown