In: Statistics and Probability
Question 1
Sales | Advertising | Price |
157.7301 | 114.9536 | 187 |
121.1506 | 141.0268 | 186.3123 |
106.4625 | 153.3305 | 186.2964 |
127.5707 | 110.1133 | 136.1812 |
174.9113 | 159.3815 | 159.1798 |
100.1009 | 143.0154 | 182.8766 |
130.0771 | 153.8483 | 158.7549 |
158.8319 | 123.3517 | 177.6487 |
166.3804 | 151.2224 | 126.3865 |
149.9134 | 104.4393 | 157.523 |
141.8844 | 120.7072 | 126.7821 |
152.5924 | 110.5488 | 106.5236 |
102.5648 | 120.516 | 130.9825 |
137.5087 | 138.0106 | 153.2031 |
131.2427 | 122.6614 | 165.1192 |
129.1159 | 104.0119 | 112.1737 |
166.0645 | 181.9792 | 146.8946 |
100.4567 | 122.4835 | 167.7717 |
114.7491 | 122.964 | 127.3822 |
122.9083 | 126.5962 | 138.4009 |
183.8643 | 182.8872 | 168 |
101.4258 | 128.4283 | 127.2866 |
118.4291 | 152.4145 | 160.04 |
152.4756 | 184.5918 | 111.4037 |
150.6595 | 166.8079 | 111.1329 |
116.7936 | 132.5331 | 166.7229 |
107.7582 | 116.9184 | 137.8592 |
119.5469 | 124.1774 | 142.0437 |
133.1358 | 171.3747 | 150.8799 |
108.9371 | 137.8592 | 127.8202 |
178.1877 | 128.5637 | 138.8044 |
157.0583 | 142.5853 | 156.0096 |
150.625 | 183.9174 | 145.7502 |
127.2361 | 120.9435 | 185.4388 |
144.2846 | 117.768 | 117.7202 |
161.6968 | 178.6099 | 101.8665 |
149.0532 | 165.2546 | 165.0051 |
152.3349 | 140.1559 | 120.0726 |
145.2139 | 137.5114 | 113.7561 |
161.2481 | 104.6571 | 103.5632 |
141.587 | 182.3801 | 166.6539 |
137.6707 | 113.2118 | 104.9544 |
186.6548 | 117.1865 | 107.9175 |
165.5812 | 162.9686 | 141.3799 |
110.8753 | 125.3696 | 139.901 |
136.8317 | 120.2691 | 177.3965 |
149.8364 | 129.1319 | 169.6674 |
107.4874 | 175.1715 | 106.89 |
181.2995 | 180.2666 | 154.6262 |
100.7248 | 131.4843 | 131.7259 |
101.848 | 186.2991 | 182.935 |
175.2219 | 186.8301 | 163.9616 |
(i)
Sales | Advertising | Price | |
Sales | 1.000 | ||
Advertising | .249 | 1.000 | |
Price | -.130 | .151 | 1.000 |
r = -0.130
The hypothesis being tested is:
H0: = 0
H1: ≠ 0
Source | SS | df | MS | F | p-value |
Regression | 540.5628 | 1 | 540.5628 | 0.86 | .3586 |
Residual | 31,481.2638 | 50 | 629.6253 | ||
Total | 32,021.8266 | 51 |
The p-value is 0.3586.
Since the p-value (0.3586) is greater than the significance level (0.04), we fail to reject the null hypothesis.
Therefore, we cannot conclude that the relationship is significant.
(ii) The regression equation is:
y = 156.8587 - 0.1260*x
variables | coefficients | std. error | t (df=50) | p-value |
Intercept | 156.8587 | |||
Price | -0.1260 | 0.1359 | -0.927 | .3586 |
The regression equation is:
y = 104.5359 + 0.2410*x
variables | coefficients | std. error | t (df=50) | p-value |
Intercept | 104.5359 | |||
Advertising | 0.2410 | 0.1327 | 1.816 | .0754 |
(iii)
variables | coefficients | std. error | t (df=49) | p-value |
Intercept | 125.0632 | |||
Advertising | 0.2661 | 0.1335 | 1.993 | .0519 |
Price | -0.1662 | 0.1336 | -1.244 | .2194 |
The hypothesis being tested is:
H0: β1 = β2 = 0
H1: At least one βi ≠ 0
The p-value is 0.0519.
Since the p-value (0.0519) is greater than the significance level (0.05), we fail to reject the null hypothesis.
Therefore, we cannot conclude that the slope is significant.
The hypothesis being tested is:
H0: β2 = 0
H1: β2 ≠ 0
The p-value is 0.2194.
Since the p-value (0.2194) is greater than the significance level (0.05), we fail to reject the null hypothesis.
Therefore, we cannot conclude that the slope is significant.
(iv)
Predicted values for: Sales | ||
Advertising | Price | Predicted |
114.9536 | 187.0000 | 124.5652928 |
141.0268 | 186.3123 | 131.6169137 |
153.3305 | 186.2964 | 134.8932083 |
110.1133 | 136.1812 | 131.7246678 |
159.3815 | 159.1798 | 141.0105944 |
(v) The hypothesis being tested is:
H0: µ1 = µ2 = µ3
Ha: Not all means are equal
Mean | n | Std. Dev | |||
138.61153 | 52 | 25.057513 | Sales | ||
141.41712 | 52 | 25.864454 | Advertising | ||
144.85727 | 52 | 25.845311 | Price | ||
141.62864 | 156 | 25.555002 | Total | ||
ANOVA table | |||||
Source | SS | df | MS | F | p-value |
Treatment | 1,017.730953 | 2 | 508.8654763 | 0.78 | .4616 |
Error | 1,00,206.281846 | 153 | 654.9430186 | ||
Total | 1,01,224.012798 | 155 |
The p-value is 0.4616.
Since the p-value (0.4616) is greater than the significance level (0.03), we fail to reject the null hypothesis.
Therefore, we cannot conclude that not all means are equal.
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