We use letters to substitute for unknown numbers. I hope this helps. :)
Answer:
greater than is the answer
Answer:
The answer is below
Step-by-step explanation:
1)
mean (μ) = 12, SD(σ) = 2.3, sample size (n) = 65
Given that the confidence level (c) = 90% = 0.9
α = 1 - c = 0.1
α/2 = 0.05
The z score of α/2 is the same as the z score of 0.45 (0.5 - 0.05) which is equal to 1.65
The margin of error (E) is given as:
![E=Z_{\frac{\alpha}{2} }*\frac{\sigma}{\sqrt{n} } =1.65*\frac{2.3}{\sqrt{65} } =0.47](https://tex.z-dn.net/?f=E%3DZ_%7B%5Cfrac%7B%5Calpha%7D%7B2%7D%20%7D%2A%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%20%7D%20%3D1.65%2A%5Cfrac%7B2.3%7D%7B%5Csqrt%7B65%7D%20%7D%20%3D0.47)
The confidence interval = μ ± E = 12 ± 0.47 = (11.53, 12.47)
2)
mean (μ) = 23, SD(σ) = 12, sample size (n) = 45
Given that the confidence level (c) = 88% = 0.88
α = 1 - c = 0.12
α/2 = 0.06
The z score of α/2 is the same as the z score of 0.44 (0.5 - 0.06) which is equal to 1.56
The margin of error (E) is given as:
![E=Z_{\frac{\alpha}{2} }*\frac{\sigma}{\sqrt{n} } =1.56*\frac{12}{\sqrt{45} } =2.8](https://tex.z-dn.net/?f=E%3DZ_%7B%5Cfrac%7B%5Calpha%7D%7B2%7D%20%7D%2A%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%20%7D%20%3D1.56%2A%5Cfrac%7B12%7D%7B%5Csqrt%7B45%7D%20%7D%20%3D2.8)
The confidence interval = μ ± E = 23 ± 2.8 = (22.2, 25.8)