Quiz 11.2A AP Statistics Name:
Pat wants to compare the cost of one- and two-bedroom apartments in the area of her college campus. She collects data for a random sample of 10 advertisements of each type. Here are the rents for the two-bedroom apartments (in dollars per month):
595, 500, 580, 650, 675, 675, 750, 500, 495, 670
Here are the rents for the one-bedroom apartments:
500, 650, 600, 505, 450, 550, 515, 495, 650, 395
1. Pat wonders if two-bedroom apartments rent for significantly more than one-bedroom apartments. Perform a significance test to answer her question. Follow the Inference Toolbox.
Step:1:
μ1 = mean rent for two-bedroom apartment
μ2 = mean rent for one-bedroom apartment
Ho: μ1 = μ2 same mean rent for both 1 & 2 bedroom apartments
Ha: μ1 < μ2 mean rent for 1 bedroom less than 2 bedroom apartments
Step 2: (2-sample t-test)
Conditions/Assumptions:
1. SRS from ads may not be SRS from whole population, may not be independent since may come from same apt complex.
2. Some skewedness in both graphs – no outliers, both normal probability plots non-linear
Due to the uncertainty of the conditions not being met, we will proceed with caution. Our conclusions may not be indicative of the whole population.
Step 3:
Step 4:
The chance of getting a 2 sample mean that differs as much as ours does is 2.9%, given Ho is true.
Given a p-value of .029, we would reject the null hypothesis.
We have evidence that two-bedroom apartments are more expensive than one-bedroom apartments.
2. Find a 95% confidence interval for the additional cost of a second bedroom. Interpret your interval in the context of this problem.
Step 4:
We are 95% confident that the actual difference in the mean rent for one-bedroom and 2-bedroom apartments is between -$2.94 and $158.94.
Chapter 11 Quiz 11.2A