Westonci.ca is the premier destination for reliable answers to your questions, brought to you by a community of experts. Experience the ease of finding accurate answers to your questions from a knowledgeable community of professionals. Join our platform to connect with experts ready to provide precise answers to your questions in different areas.

Calculate the standard error. May normality be assumed? (Round your answers to 4 decimal places.)

| | | Standard Error | Normality |
|-------|-------------|----------------|-----------|
| (a) | [tex]\( n = 27, \pi = 0.32 \)[/tex] | | |
| (b) | [tex]\( n = 58, \pi = 0.45 \)[/tex] | | |
| (c) | [tex]\( n = 119, \pi = 0.39 \)[/tex] | | |
| (d) | [tex]\( n = 359, \pi = 0.004 \)[/tex] | | |


Sagot :

To answer these questions about standard error and normality, we need to follow a specific procedure for each part. The standard error for a proportion is calculated using the formula:

[tex]\[ \text{Standard Error} = \sqrt{\frac{\pi (1 - \pi)}{n}} \][/tex]

We also need to verify the normality condition, which states that the sample size and the proportion should satisfy:

[tex]\[ n \pi \geq 5 \quad \text{and} \quad n (1 - \pi) \geq 5 \][/tex]

Let's discuss each part step-by-step.

### (a) Given: [tex]\( n = 27 \)[/tex], [tex]\( \pi = 0.32 \)[/tex]

1. Standard Error Calculation:
[tex]\[ \text{Standard Error} = \sqrt{\frac{0.32 \times (1 - 0.32)}{27}} = 0.0898 \][/tex]

2. Normality Condition:
[tex]\[ n \pi = 27 \times 0.32 = 8.64 \quad (\text{>= 5}) \][/tex]
[tex]\[ n (1 - \pi) = 27 \times 0.68 = 18.36 \quad (\text{>= 5}) \][/tex]

Both conditions are satisfied, so normality can be assumed.

### Result:
- Standard Error: 0.0898
- Normality: True

### (b) Given: [tex]\( n = 58 \)[/tex], [tex]\( \pi = 0.45 \)[/tex]

1. Standard Error Calculation:
[tex]\[ \text{Standard Error} = \sqrt{\frac{0.45 \times (1 - 0.45)}{58}} = 0.0653 \][/tex]

2. Normality Condition:
[tex]\[ n \pi = 58 \times 0.45 = 26.1 \quad (\text{>= 5}) \][/tex]
[tex]\[ n (1 - \pi) = 58 \times 0.55 = 31.9 \quad (\text{>= 5}) \][/tex]

Both conditions are satisfied, so normality can be assumed.

### Result:
- Standard Error: 0.0653
- Normality: True

### (c) Given: [tex]\( n = 119 \)[/tex], [tex]\( \pi = 0.39 \)[/tex]

1. Standard Error Calculation:
[tex]\[ \text{Standard Error} = \sqrt{\frac{0.39 \times (1 - 0.39)}{119}} = 0.0447 \][/tex]

2. Normality Condition:
[tex]\[ n \pi = 119 \times 0.39 = 46.41 \quad (\text{>= 5}) \][/tex]
[tex]\[ n (1 - \pi) = 119 \times 0.61 = 72.59 \quad (\text{>= 5}) \][/tex]

Both conditions are satisfied, so normality can be assumed.

### Result:
- Standard Error: 0.0447
- Normality: True

### (d) Given: [tex]\( n = 359 \)[/tex], [tex]\( \pi = 0.004 \)[/tex]

1. Standard Error Calculation:
[tex]\[ \text{Standard Error} = \sqrt{\frac{0.004 \times (1 - 0.004)}{359}} = 0.0033 \][/tex]

2. Normality Condition:
[tex]\[ n \pi = 359 \times 0.004 = 1.436 \quad (\text{< 5}) \][/tex]
[tex]\[ n (1 - \pi) = 359 \times 0.996 = 357.564 \quad (\text{>= 5}) \][/tex]

The first condition is not satisfied, so normality cannot be assumed.

### Result:
- Standard Error: 0.0033
- Normality: False

In summary:

[tex]\[ \begin{array}{|c|c|c|c|} \hline & n & \pi & \text{Standard Error} & \text{Normality} \\ \hline (a) & 27 & 0.32 & 0.0898 & \text{True} \\ \hline (b) & 58 & 0.45 & 0.0653 & \text{True} \\ \hline (c) & 119 & 0.39 & 0.0447 & \text{True} \\ \hline (d) & 359 & 0.004 & 0.0033 & \text{False} \\ \hline \end{array} \][/tex]