1. Using regression analysis, what is the highest fixed cost per month you associate with a 95% confidence interval?

2. What is the R² associated with the regression model for total costs when using number of listings as a predictor variable?

3. Using regression analysis, what is the probability that Dana's variable cost per listing are actually $0?

Dana owns her own real estate agency. She has been working hard to increase her client base. She offers the most comprehensive advertising campaign in the city and it has been paying off by the steady increase in the number of listings over the last several months. However, Dana is concerned that her extensive cost for advertising is eating into her profits. It is difficult to determine how much she spends on advertising for each listing because some of her advertising sources are fixed amounts each month and others are more variable in nature. She would like to analyze the following information to determine how her advertising costs behave based on the number of listings.

Month	Number of Listings	Advertising Cost
March	22	$15,280
April	26	17,640
May	35	23,145
June	42	27,205
July	48	30,565
August	51	32,485
September	50	31,835
October	56	36,020
November	54	34,920