In: Statistics and Probability
Construct two 95% confidence intervals for each sample.
SD = | $35,989.61 |
Apply the population standard deviation (σ) in the formula to form z-distribution since the population standard deviation is known.
Loan Amount | Type Sample 1 |
$ 30,500.00 | Commercial |
$ 78,500.00 | Commercial |
$ 90,000.00 | Commercial |
$ 19,000.00 | Commercial |
$ 36,000.00 | Commercial |
$ 89,500.00 | Commercial |
$ 22,000.00 | Commercial |
$ 65,000.00 | Commercial |
$ 109,000.00 | Commercial |
$ 5,500.00 | Commercial |
$ 93,500.00 | Commercial |
$ 6,000.00 | Commercial |
$ 85,500.00 | Commercial |
$ 98,000.00 | Commercial |
$ 57,000.00 | Commercial |
$ 59,000.00 | Commercial |
$ 8,500.00 | Commercial |
$ 9,000.00 | Commercial |
$ 16,000.00 | Commercial |
$ 71,000.00 | Commercial |
$ 79,000.00 | Commercial |
$ 32,500.00 | Commercial |
$ 3,500.00 | Commercial |
$ 95,500.00 | Commercial |
$ 75,500.00 | Commercial |
$ 90,500.00 | Commercial |
$ 25,500.00 | Commercial |
$ 122,000.00 | Commercial |
$ 27,500.00 | Commercial |
$ 112,500.00 | Commercial |
$ 91,000.00 | Commercial |
$ 107,500.00 | Commercial |
$ 75,500.00 | Commercial |
$ 73,000.00 | Commercial |
$ 17,500.00 | Commercial |
$ 91,000.00 | Commercial |
$ 23,500.00 | Commercial |
$ 111,000.00 | Commercial |
$ 66,500.00 | Commercial |
$ 21,000.00 | Commercial |
$ 21,500.00 | Commercial |
$ 12,000.00 | Commercial |
$ 45,000.00 | Commercial |
$ 123,000.00 | Commercial |
$ 18,500.00 | Commercial |
$ 6,500.00 | Commercial |
$ 118,500.00 | Commercial |
$ 91,000.00 | Commercial |
$ 23,000.00 | Commercial |
$ 38,500.00 | Commercial |
$ 96,000.00 | Commercial |
$ 91,000.00 | Commercial |
$ 16,500.00 | Commercial |
$ 36,000.00 | Commercial |
$ 96,000.00 | Commercial |
$ 96,500.00 | Commercial |
$ 86,500.00 | Commercial |
$ 46,000.00 | Commercial |
$ 19,000.00 | Commercial |
$ 84,500.00 | Commercial |
$ 57,000.00 | Commercial |
$ 29,000.00 | Commercial |
$ 124,500.00 | Commercial |
$ 12,000.00 | Commercial |
$ 50,000.00 | Commercial |
$ 66,000.00 | Commercial |
$ 48,000.00 | Commercial |
$ 44,000.00 | Commercial |
$ 92,000.00 | Commercial |
$ 16,000.00 | Commercial |
$ 39,500.00 | Commercial |
$ 9,000.00 | Commercial |
$ 43,000.00 | Commercial |
$ 91,000.00 | Commercial |
$ 73,000.00 | Commercial |
$ 90,500.00 | Commercial |
$ 64,500.00 | Commercial |
$ 112,500.00 | Commercial |
$ 82,500.00 | Commercial |
$ 86,500.00 | Commercial |
$ 10,000.00 | Commercial |
$ 31,500.00 | Commercial |
$ 41,500.00 | Commercial |
$ 39,000.00 | Commercial |
$ 40,500.00 | Commercial |
$ 69,000.00 | Commercial |
$ 66,500.00 | Commercial |
$ 60,000.00 | Commercial |
$ 54,000.00 | Commercial |
$ 122,000.00 | Commercial |
$ 44,000.00 | Commercial |
$ 33,000.00 | Commercial |
$ 97,000.00 | Commercial |
$ 103,000.00 | Commercial |
$ 97,500.00 | Commercial |
$ 110,500.00 | Commercial |
$ 21,500.00 | Commercial |
$ 116,000.00 | Commercial |
$ 72,000.00 | Commercial |
$ 66,500.00 | Commercial |
$ 79,000.00 | Commercial |
$ 36,000.00 | Commercial |
$ 84,000.00 | Commercial |
$ 99,000.00 | Commercial |
$ 4,000.00 | Commercial |
$ 115,000.00 | Commercial |
$ 86,000.00 | Commercial |
$ 42,000.00 | Commercial |
$ 117,000.00 | Commercial |
$ 18,500.00 | Commercial |
$ 123,000.00 | Commercial |
$ 109,000.00 | Commercial |
$ 37,500.00 | Commercial |
$ 53,500.00 | Commercial |
$ 36,000.00 | Commercial |
$ 62,000.00 | Commercial |
$ 44,500.00 | Commercial |
$ 3,500.00 | Commercial |
$ 56,500.00 | Commercial |
$ 82,000.00 | Commercial |
$ 7,500.00 | Commercial |
$ 94,000.00 | Commercial |
$ 89,000.00 | Commercial |
$ 6,500.00 | Commercial |
$ 9,500.00 | Commercial |
$ 89,000.00 | Commercial |
$ 6,500.00 | Commercial |
$ 95,500.00 | Commercial |
$ 23,500.00 | Commercial |
$ 59,000.00 | Commercial |
$ 31,000.00 | Commercial |
$ 22,500.00 | Commercial |
$ 35,000.00 | Commercial |
$ 59,000.00 | Commercial |
$ 31,500.00 | Commercial |
$ 40,500.00 | Commercial |
$ 73,500.00 | Commercial |
$ 21,500.00 | Commercial |
$ 45,000.00 | Commercial |
$ 79,500.00 | Commercial |
$ 110,500.00 | Commercial |
$ 112,000.00 | Commercial |
$ 12,500.00 | Commercial |
$ 105,000.00 | Commercial |
$ 92,500.00 | Commercial |
$ 65,000.00 | Commercial |
$ 7,500.00 | Commercial |
$ 6,000.00 | Commercial |
$ 73,500.00 | Commercial |
$ 98,500.00 | Commercial |
$ 59,500.00 | Commercial |
$ 31,000.00 | Commercial |
$ 67,000.00 | Commercial |
$ 28,500.00 | Commercial |
$ 63,500.00 | Commercial |
$ 108,500.00 | Commercial |
$ 101,000.00 | Commercial |
$ 120,000.00 | Commercial |
$ 63,500.00 | Commercial |
$ 74,000.00 | Commercial |
$ 40,000.00 | Commercial |
$ 109,500.00 | Commercial |
$ 114,500.00 | Commercial |
$ 89,000.00 | Commercial |
$ 86,000.00 | Commercial |
$ 69,500.00 | Commercial |
$ 85,000.00 | Commercial |
$ 5,500.00 | Commercial |
$ 112,500.00 | Commercial |
$ 95,000.00 | Commercial |
$ 70,500.00 | Commercial |
$ 33,000.00 | Consumer |
$ 89,500.00 | Consumer |
$ 40,000.00 | Consumer |
$ 76,000.00 | Consumer |
$ 72,500.00 | Consumer |
$ 123,500.00 | Consumer |
$ 9,000.00 | Consumer |
$ 6,500.00 | Consumer |
$ 113,500.00 | Consumer |
$ 86,000.00 | Consumer |
$ 108,500.00 | Consumer |
$ 24,500.00 | Consumer |
$ 78,000.00 | Consumer |
$ 70,000.00 | Consumer |
$ 125,000.00 | Consumer |
$ 32,500.00 | Consumer |
$ 15,000.00 | Consumer |
$ 16,000.00 | Consumer |
$ 40,500.00 | Consumer |
$ 101,000.00 | Consumer |
$ 12,000.00 | Consumer |
$ 33,000.00 | Consumer |
$ 50,000.00 | Consumer |
$ 81,500.00 | Consumer |
$ 17,500.00 | Consumer |
$ 45,000.00 | Consumer |
$ 56,500.00 | Consumer |
$ 39,000.00 | Consumer |
$ 123,500.00 | Consumer |
$ 118,000.00 | Consumer |
$ 46,500.00 | Consumer |
$ 49,000.00 | Consumer |
$ 105,500.00 | Consumer |
$ 15,500.00 | Consumer |
$ 94,500.00 | Consumer |
$ 20,000.00 | Consumer |
$ 83,500.00 | Consumer |
$ 74,000.00 | Consumer |
$ 33,000.00 | Consumer |
$ 122,500.00 | Consumer |
$ 64,000.00 | Consumer |
$ 11,500.00 | Consumer |
$ 124,000.00 | Consumer |
$ 33,000.00 | Consumer |
$ 14,500.00 | Consumer |
$ 11,500.00 | Consumer |
$ 83,500.00 | Consumer |
$ 101,000.00 | Consumer |
$ 62,000.00 | Consumer |
$ 75,500.00 | Consumer |
$ 18,500.00 | Consumer |
$ 56,000.00 | Consumer |
$ 66,500.00 | Consumer |
$ 42,500.00 | Consumer |
$ 44,500.00 | Consumer |
$ 72,500.00 | Consumer |
$ 20,000.00 | Consumer |
$ 37,500.00 | Consumer |
$ 5,500.00 | Consumer |
$ 94,000.00 | Consumer |
$ 98,000.00 | Consumer |
$ 94,000.00 | Consumer |
$ 57,500.00 | Consumer |
$ 30,000.00 | Consumer |
$ 120,500.00 | Consumer |
$ 8,000.00 | Consumer |
$ 108,500.00 | Consumer |
$ 6,000.00 | Consumer |
$ 106,500.00 | Consumer |
$ 31,000.00 | Consumer |
$ 52,500.00 | Consumer |
$ 58,500.00 | Consumer |
$ 105,000.00 | Consumer |
$ 4,500.00 | Consumer |
$ 76,500.00 | Consumer |
$ 72,500.00 | Consumer |
$ 107,000.00 | Consumer |
$ 98,500.00 | Consumer |
$ 87,000.00 | Consumer |
$ 118,500.00 | Consumer |
$ 105,000.00 | Consumer |
$ 64,500.00 | Consumer |
$ 16,500.00 | Consumer |
$ 77,500.00 | Consumer |
$ 40,000.00 | Consumer |
$ 16,000.00 | Consumer |
$ 111,000.00 | Consumer |
$ 41,000.00 | Consumer |
$ 7,000.00 | Consumer |
$ 35,000.00 | Consumer |
$ 90,000.00 | Consumer |
$ 21,500.00 | Consumer |
$ 71,500.00 | Consumer |
$ 115,500.00 | Consumer |
$ 17,500.00 | Consumer |
$ 8,500.00 | Consumer |
$ 72,000.00 | Consumer |
$ 56,500.00 | Consumer |
$ 45,500.00 | Consumer |
$ 49,000.00 | Consumer |
$ 43,500.00 | Consumer |
$ 124,000.00 | Consumer |
$ 41,000.00 | Consumer |
$ 10,500.00 | Consumer |
$ 102,000.00 | Consumer |
$ 113,500.00 | Consumer |
$ 36,500.00 | Consumer |
$ 15,000.00 | Consumer |
$ 114,500.00 | Consumer |
$ 121,500.00 | Consumer |
$ 76,000.00 | Consumer |
$ 64,500.00 | Consumer |
$ 27,000.00 | Consumer |
$ 77,500.00 | Consumer |
$ 63,500.00 | Consumer |
$ 76,500.00 | Consumer |
$ 48,500.00 | Real Estate |
$ 117,500.00 | Real Estate |
$ 57,000.00 | Real Estate |
$ 82,000.00 | Real Estate |
$ 118,000.00 | Real Estate |
$ 70,000.00 | Real Estate |
$ 106,000.00 | Real Estate |
$ 56,500.00 | Real Estate |
$ 39,000.00 | Real Estate |
$ 119,000.00 | Real Estate |
$ 93,000.00 | Real Estate |
$ 11,000.00 | Real Estate |
$ 66,000.00 | Real Estate |
$ 19,500.00 | Real Estate |
$ 106,500.00 | Real Estate |
$ 23,000.00 | Real Estate |
$ 98,500.00 | Real Estate |
$ 30,500.00 | Real Estate |
$ 120,500.00 | Real Estate |
$ 82,500.00 | Real Estate |
$ 102,500.00 | Real Estate |
$ 22,000.00 | Real Estate |
$ 112,500.00 | Real Estate |
$ 112,000.00 | Real Estate |
$ 24,500.00 | Real Estate |
$ 57,000.00 | Real Estate |
$ 74,000.00 | Real Estate |
$ 102,500.00 | Real Estate |
$ 29,000.00 | Real Estate |
$ 81,500.00 | Real Estate |
$ 34,000.00 | Real Estate |
$ 112,000.00 | Real Estate |
$ 68,000.00 | Real Estate |
$ 109,500.00 | Real Estate |
$ 32,000.00 | Real Estate |
$ 32,000.00 | Real Estate |
$ 99,000.00 | Real Estate |
$ 93,500.00 | Real Estate |
$ 95,000.00 | Real Estate |
$ 89,000.00 | Real Estate |
$ 83,000.00 | Real Estate |
$ 117,000.00 | Real Estate |
$ 58,000.00 | Real Estate |
$ 12,500.00 | Real Estate |
$ 102,500.00 | Real Estate |
$ 81,000.00 | Real Estate |
$ 125,000.00 | Real Estate |
$ 63,500.00 | Real Estate |
$ 107,500.00 | Real Estate |
$ 9,000.00 | Real Estate |
$ 110,500.00 | Real Estate |
$ 64,500.00 | Real Estate |
$ 69,500.00 | Real Estate |
$ 71,000.00 | Real Estate |
$ 81,500.00 | Real Estate |
$ 89,000.00 | Real Estate |
$ 61,500.00 | Real Estate |
$ 65,000.00 | Real Estate |
$ 123,000.00 | Real Estate |
$ 65,000.00 | Real Estate |
$ 45,000.00 | Real Estate |
$ 25,000.00 | Real Estate |
$ 17,000.00 |
Real Estate |
GIVEN:
Population standard deviation
When the population standard deviation is known, the formula for a confidence interval (CI) for a population mean is given by,
where is the sample mean.
is the population standard deviation.
n is the sample size, and
z* represents the appropriate z*-value from the standard normal distribution for desired confidence level.
For the given problem the z*-value from the standard normal distribution for 95% confidence level is 1.96.
SAMPLE 1 (COMMERCIAL TYPE):
Let us consider sample 1 (commercial type)
Total number of observations from sample 1 (n) = 171
The sample mean is defined as the average of n observations from the sample and it is considered to be the estimate of pupulation mean.
I have used excel function to find the sample mean given by,
"=AVERAGE(select array of values from sample 1)"
Thus the mean of sample 1
Population standard deviation
The z*-value from the standard normal distribution for 95% confidence level is 1.96.
The 95% confidence interval (CI) for a population mean is given by,
Thus 95% confidence interval for mean loan amount in the sample 1 (Commercial Type) is .
SAMPLE 2 (CONSUMER TYPE):
Let us consider sample 2 (consumer type)
Total number of observations from sample 2 (n) = 116
The sample mean is defined as the average of n observations from the sample and it is considered to be the estimate of pupulation mean.
I have used excel function to find the sample mean given by,
"=AVERAGE(select array of values from sample 2)"
Thus the mean of sample 2
Population standard deviation
The z*-value from the standard normal distribution for 95% confidence level is 1.96.
The 95% confidence interval (CI) for a population mean is given by,
Thus 95% confidence interval for mean loan amount in the sample 2 (Consumer Type) is
SAMPLE 3 (REAL ESTATE TYPE):
Let us consider sample 3 (Real estate type)
Total number of observations from sample 3 (n) = 63
The sample mean is defined as the average of n observations from the sample and it is considered to be the estimate of pupulation mean.
I have used excel function to find the sample mean given by,
"=AVERAGE(select array of values from sample 2)"
Thus the mean of sample 3
Population standard deviation
The z*-value from the standard normal distribution for 95% confidence level is 1.96.
The 95% confidence interval (CI) for a population mean is given by,
Thus 95% confidence interval for mean loan amount in the sample 3 (Real Estate Type) is