Answer:
135.05 ; 2.762 ; (133.201, 136.899) ; (132.840, 137.260)
Step-by-step explanation:
Given the data:
Urban area Price/liter
St. John, NL 137.1
Halifax 133.6
Montreal 136.2
Regina 132.3
Saskatoon 132.2
Yellowknife 138.9
Mean = (137.1 + 133.6 + 136.2 + 132.3 + 132.2 + 138.9) / 6
= 810.3 / 6
= 135.05
Standard deviation (σ) : √Σ(X - mean)²/n-1
(137.1 - 135.05)^2 + (133.6 - 135.05)^2 + (136.2 - 135.05)^2 + (132.3 - 135.05)^2 + (132.2 - 135.05)^2+ (138.9 - 135.05)^2 = 38.135
√(38.135 / (6 - 1))
= √7.627
= 2.7617023
= 2.762
C.)
90% confidence interval of the mean :
Mean ± Zcrit * σ/√n
Zcrit at 90% = 1.64
135.05 ± 1.64 * (2.762/√6)
135.05 ± 1.64 * 1.1275817
Lower Value = (135.05 - (1.64 * 1.1275817)) = 133.201
Upper Value = (135.05 + (1.64 * 1.1275817))) = 136.899
Confidence interval = (133.201, 136.899)
D.)
95% confidence interval of the mean :
Mean ± Zcrit * σ/√n
Zcrit at 95% = 1.96
135.05 ± 1.96 * (2.762/6)
135.05 ± 1.96 * 1.1275817
Lower Value = (135.05 - (1.96 * 1.1275817)) = 132.840
Upper Value = (135.05 + (1.96 * 1.1275817)) = 137.260
Confidence interval = (132.840, 137.260)
