Question

Part I – The Question

At the end of a long day of shopping, Katelyn and Lisa were walking out to Lisa’s car, ready to go home. Putting their

shopping bags in the trunk, Lisa slipped into the driver’s seat while Katelyn took her position as passenger.

Lisa put the key in the ignition and absently said to Katelyn, “Looks like someone’s waiting for our spot.” Lisa started

the car. Th e vehicle waiting for their spot honked.

“Th at drives me nuts,” Lisa said in response to the horn. “I’m going, I’m going. Be patient,” she muttered under her

breath to the driver of the other car. Although she had been about to put the car in reverse and pull out of the spot,

she dug into her purse for her lipstick.

“Lisa, that other car is waiting. Why aren’t you leaving?” asked Katelyn.

“I will,” said Lisa. “I can’t put lipstick on while I’m driving. Besides, it’s my spot and I can stay in it as long as I want.”

“Now you’re being rude,” Katelyn scolded her friend. “I always try to leave as quickly as I can when another car is waiting.”

“You do not,” Lisa responded. “I’ve ridden with you and you make the other person wait.”

Lisa pulled out of the parking spot as Katelyn shot back: “Do not.”

“Do too,” Lisa continued the argument. “Everyone takes longer to leave a parking spot when someone’s waiting. It’s an

instinctual thing—we’re defending our territory.”

Katelyn responded with a snort. “Instinct? I don’t think so. People are nicer than that. Except for a few rude people

like you,” she said teasingly, “most of us leave faster when someone’s waiting.”

“As a psych major it seems like that’s something you could study,” Lisa responded.

“Maybe I’ll make that my next project for my research methods class,” Katelyn replied. “I’ll let you know what I fi nd out.”

Questions

Help Katelyn fi nd out whether she is right or Lisa is right. In groups of 2–3:

1. Identify the specifi c research question(s) implied by their discussion.

2. What hypothesis would your group suggest?

3. What predictions can you make if your hypothesis is correct?

4. How could you test the predictions? In other words, if you were to investigate this issue, how might you do it?

Answer 1

1. What Katelyn says is that (Few) Nicer people leave early than the rude ones. So we can be interested in figuring out whether 'Nicer people leave a parking lot early when a car is waiting behind, as compared to rude people or not'

2. 3.

If the hypothesis is correct (i.e. the null is rejected) then, we would conclude that Katelyn is indeed right as nicer people, in general, leave early than the rude ones.

4.

There's a big source of ambiguity to decide who is rude and who isn't. I suggest the following:

- Select a large group of individuals randomly for the study, while don't let them know. (a university is a very good choice for finding such a large group)

- Now, use some social experiment to classify them as rude/nice (Katelyn is a Psych major). An example can be how they react to strangers persistently asking them questions. Who gets impatient very fast and replies rudely, classify that subject as 'Rude' else as 'Nice'.

- Now hire somebody to honk at them in a parking lot and record their leaving times, from the moment the honking starts.

-Let's assume that we have n individuals, n1 of them are 'Nice', n2 are 'Rude'. Let the leaving times for the Nice people be: while for the Rude ones be: . The samples are independent.

So we can now conduct an independent samples t-test to test the hypothesis.

A NOTE: Katelyn admits that the number of 'Rude' people are less, so possibly in this observational study, the samples corresponding to 'Rude' people would be low. This would cause some problems as the power of the test would be low. Thus, if the test is rejeced, then Katelyn is definitely true. But the chance of erroneous acceptance of null is higher (in which case we are inconclusive. It doesn't imply that the mean leaving times are equal for the two groups.)