In: Statistics and Probability
# |
Variable |
Variable |
1 |
205 |
1500 |
2 |
70 |
750 |
3 |
199 |
1500 |
4 |
151 |
1250 |
5 |
181 |
1250 |
6 |
217 |
1250 |
7 |
94 |
1000 |
8 |
298 |
2000 |
9 |
135 |
1000 |
10 |
211 |
1500 |
11 |
116 |
1250 |
12 |
72 |
500 |
13 |
82 |
500 |
14 |
206 |
1500 |
15 |
245 |
2000 |
16 |
219 |
1500 |
17 |
63 |
750 |
18 |
200 |
1500 |
19 |
151 |
1250 |
20 |
44 |
500 |
What is the significance of the slope. Use a significance level of 0.05
What is the coefficient of determination
X | Y | X*Y | X2 | Y2 |
205.00 | 1,500.00 | 3,07,500.00 | 42,025.00 | 22,50,000.00 |
70.00 | 750.00 | 52,500.00 | 4,900.00 | 5,62,500.00 |
199.00 | 1,500.00 | 2,98,500.00 | 39,601.00 | 22,50,000.00 |
151.00 | 1,250.00 | 1,88,750.00 | 22,801.00 | 15,62,500.00 |
181.00 | 1,250.00 | 2,26,250.00 | 32,761.00 | 15,62,500.00 |
217.00 | 1,250.00 | 2,71,250.00 | 47,089.00 | 15,62,500.00 |
94.00 | 1,000.00 | 94,000.00 | 8,836.00 | 10,00,000.00 |
298.00 | 2,000.00 | 5,96,000.00 | 88,804.00 | 40,00,000.00 |
135.00 | 1,000.00 | 1,35,000.00 | 18,225.00 | 10,00,000.00 |
211.00 | 1,500.00 | 3,16,500.00 | 44,521.00 | 22,50,000.00 |
116.00 | 1,250.00 | 1,45,000.00 | 13,456.00 | 15,62,500.00 |
72.00 | 500.00 | 36,000.00 | 5,184.00 | 2,50,000.00 |
82.00 | 500.00 | 41,000.00 | 6,724.00 | 2,50,000.00 |
206.00 | 1,500.00 | 3,09,000.00 | 42,436.00 | 22,50,000.00 |
245.00 | 2,000.00 | 4,90,000.00 | 60,025.00 | 40,00,000.00 |
219.00 | 1,500.00 | 3,28,500.00 | 47,961.00 | 22,50,000.00 |
63.00 | 750.00 | 47,250.00 | 3,969.00 | 5,62,500.00 |
200.00 | 1,500.00 | 3,00,000.00 | 40,000.00 | 22,50,000.00 |
151.00 | 1,250.00 | 1,88,750.00 | 22,801.00 | 15,62,500.00 |
44.00 | 500.00 | 22,000.00 | 1,936.00 | 2,50,000.00 |
3,159.00 | 24,250.00 | 43,93,750.00 | 5,94,055.00 | 3,31,87,500.00 |
CORRELATION |
Based on the above table, the
following is calculated:
|
Correlation Significance Check |
Let ρ = population correlation
coefficient (unknown) r = sample correlation coefficient (known; calculated from sample data) Null and Alternative hypothesis: H0:ρ=0 i.e. population correlation coefficient is 'close to 0' HA:ρ≠0 i.e. population correlation coefficient is 'significantly different from 0' Value of correlation coefficient: r=0.9393 Degrees of freedom The sample size is n=20, so then the number of degrees of freedom is df = n-2 = 20 - 2 = 18 Table of Critical Values Method Critical region: The corresponding critical correlation value rc for a significance level of α=0.05, for a Two-tailed test is: rc=0.4438 Rejection Region Observe that in this case, the null hypothesis H0:ρ=0 is rejected if |r|>rc=0.4438. Decision about the null hypothesis Based on the sample correlation provided, we have that |r|=0.9393>rc=0.4438, from which is concluded that the null hypothesis is rejected. T-statistic Method Test statistic: The value of the test statistic is calculated using the following formula: Decision about the null hypothesis: Since it is observed that |t|=11.6138 > tc=2.1009, it is then concluded that the null hypothesis is rejected. The p-value is 0 Using the P-value approach: The p-value is p=0, and since p=0≤0.05, it is concluded that the null hypothesis is rejected. Conclusion It is concluded that the null hypothesis Ho is rejected. Therefore, there is enough evidence to claim that the correlation coefficient is different than 0, at the 0.05 significance level. |
Coefficient of determination