Which of the following examples represents a proportional relationship? A. Wes is making an online purchase. He pays $3 per item plus $5 for shipping.
B. Wendy's cell phone plan is $20 a month plus $0.10 per minute.
C. Kristin is buying lunch meat from her local deli. It is $4.95 per pound.
D. Jessica is a member of the local book club. She pays $10 a month for her membership but gets her books for $3 each.

According to a research study, parents with young children slept 6.4 hours each night last year, on average. a random sample of 18 parents with young children was surveyed and the mean amount of time per night each parent slept was 6.8. this data has a sample standard deviation of 0.9. (assume that the scores are normally distributed.) researchers conduct a one-mean hypothesis at the 5% significance level, to test if the mean amount of time parents with young children sleep per night is greater than the mean amount of time last year. the null and alternative hypotheses are h0: μ=6.4 and ha: μ> 6.4, which is a right-tailed test. the test statistic is determined to be t0=1.89 using the partial t-table below, determine the critical value(s). if there is only one critical value, leave the second answer box blank.