7.44 Null hypotheses and research hypotheses: For each of the following examples, state the null hypothesis and the research hypothesis, in both words and symbolic notation:

a. Musician David Teie worked with animal researchers to develop music specifically for cats—music that a typical cat might find relaxing (Stanford, 2015). Imagine that you decided to study whether cat-specific music led to decreased heart rate in feline listeners. Use a one-tailed hypothesis.

b. The National Sleep Foundation (2015) encourages U.S. high schools to start later in the morning to improve teenagers’ sleep and school performance. Imagine you decide to conduct a study to see if teens who get to sleep an hour later have different grades than those who don’t.

c. Smartphones are everywhere, and we are now available to our friends and families almost all of the time. Does this translate into a change in the closeness of our longdistance relationships?