1. Gulf Real Estate Properties
Fernando González
Ricardo Siller
Tania Elizabeth
Santiestéban Treviño

2. Gulf Real Estate Properties
 Gulf Real Estate Properties, Inc., is a real state firm located in
Southwest Florida. The company, which advertises itself as
“expert in the real state market,” monitors condominium
sales by collecting data on location, list price, and number
of days it takes to sell each unit.
 Each condominium is classified as Gulf View if its located
directly on the Gulf of Mexico or No Gulf View if its located
on th bay or a golf course, near but not on the Gulf. Sample
data from the Multiple Listing Service in Naples, Florida,
provided recent sales data for 40 Gulf View Condominiums
and 18 No Gulf View condominiums.
 Prices are in thousands of dollars. The data are shown in the
book page 325.

3. Descriptive Statistics (Gulf View
Condominiums)
 List Price: Gulf View
Sample Size 40
Minimum $169,900
Maximum $975,000
Range $805,100
Median $437,000
Mean $474,007.50
St. Dev. $197,290.03
 Sales Price: Gulf View
Sample Size 40
Minimum $165,000
Maximum $975,000
Range $810,000
Median $417,500
Mean $454,222.50
St. Dev. $192,517.75
 Days to Sell: Gulf View
Sample Size 40
Minimum 28
Maximum 282
Range 254
Median 96
Mean 106.00
St. Dev. 52.22

4. Descriptive Statistics (No Gulf View
Condominiums)
 List Price: No Gulf View
Sample Size 18
Minimum $148,000
Maximum $322,000
Range $174,000
Median $212,500
Mean $212,805.56
St. Dev. $48,945.28
 Sales Price: No Gulf
View
Sample Size 18
Minimum $135,500
Maximum $292,500
Range $157,000
Median $203,500
Mean $203,188.89
St. Dev. $43,891.72
 Days to Sell: No Gulf
View
Sample Size 18
Minimum 48
Maximum 338
Range 290
Median 126
Mean 135.00
St. Dev. 76.30

5. Comparison of the Descriptive
Statistics (1/2)
 List price:
 The Gulf View condos have a higher average listing price than
No Gulf View Condos ($474,007.50 vs. $212,805.56).
 The Gulf View condos also have a higher median listing price
than No Gulf View Condos ($437,000 vs. $212,500).
 The data for the Gulf View condos are more variable than the
data for the No Gulf View condos (larger range and standard
deviation).

6. Comparison of the Descriptive
Statistics (2/2)
 Sales Price:
 The Gulf View condos have a higher average sales price than No
Gulf View Condos ($454,222.50 vs. $203,188.89).
 The Gulf View condos also have a higher median sales price than No
Gulf View Condos ($417,500 vs. $203,500).
 The data for the Gulf View condos are more variable than the data
for the No Gulf View condos (larger range and standard deviation).
 Conclusions: The Gulf View condos seem to be in higher demand
than the No Gulf View condos as evidenced by their higher
prices and shorter time to sell.

7. Confidence Interval. Sales Price (Gulf View
Condominiums)
 Data:
Sample Size (n) 40
Sample Mean (X-bar) 454.2225
Sample Standard
Deviation (S)
192.5177
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 39
Z value (0.9750) 1.96
 Interval (Large-Sample, s unknown)
 Conclusion: With a 95% confidence
we can expect that population
mean of sales price (gulf view
condominium) is within this range
x z
s
n
 /2
Interval
(392.65, 515.79)

8. Confidence Interval. Days to sell (Gulf View
Condominiums)
 Data:
Sample Size (n) 40
Sample Mean (X-bar) 106
Sample Standard
Deviation (S)
52.2160
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 39
Z value (0.9750) 1.96
 Interval (Large-Sample, s unknown)
 Conclusion: With a 95% confidence
we can expect that population
mean of days to sell (gulf view
condominium) is within this range
x z
s
n
 /2
Interval
(89.30, 122.70)

9. Confidence Interval. Sales Price (No Gulf View
Condominiums)
 Data:
 Interval (Small-Sample, s unknown)
 Population is normally distributed and s
unknown
 Conclusion: With a 95% confidence we can
expect that population mean of sales price (
no gulf view condominium) is within this
range
Sample Size (n) 18
Sample Mean (X-bar) 203.1888
Sample Standard
Deviation (S)
43.8917
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 17
T-value (0.025, 17) 2.110
n
s
tx 2/
Interval
(181.36, 225.02)

10. Confidence Interval. Days to sell (No Gulf View
Condominium)
 Data:
Sample Size (n) 18
Sample Mean (X-bar) 135
Sample Standard
Deviation (S)
76.2997
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 17
T-value (0.025, 17) 2.110
 Interval (Small-Sample, s unknown)
 Population is normally distributed and s
unknown
 Conclusion: With a 95% confidence we can
expect that population mean of days to sell (
no gulf view condominium) is within this
range.
n
s
tx 2/
Interval
(97.06, 172.94)

11. Sample size. Sales Price (Gulf View
Condominiums)
 95% confidence level
 Margin of error: $40,000. E=40
Sample Size (n) 40
Sample Mean (X-bar) 454.2225
Sample Standard
Deviation (S)
192.5177
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 39
Z value(0.975) 1.96
E z
n
 
s
/2
n
z
E

( )/ s2
2 2
2
n size
88.98 = 89

12. Sample size. Sales Price (No Gulf View
Condominiums)
 95% confidence level
 Margin of error: $15,000. E=15
n
z
E

( )/ s2
2 2
2
Sample Size (n) 18
Sample Mean (X-bar) 203.1888
Sample Standard
Deviation (S)
43.8917
Confidence level (%) 95%
Alpha (α) 0.05
Degrees of freedom (n-1) 17
Z value(0.975) 1.96
E z
n
 
s
/2
n size
32.89 = 33

13. Estimation New Gulf View
Condominium
 A Gulf View condominium sells on average 4.2% below its
list price.
 The estimated selling price is $589,000 x .958 = $564,262.
Using the mean days, it is estimated to sell in about 106
days.

14. Estimation New No Gulf View
Condominium
 A No Gulf View condominium sells on average 4.5%
below its list price.
 The estimated selling price is $285,000 x .955 = $272,175.
Using the mean days, it is estimated to sell in about 135
days.

15. And That’s it! Thank you