Answer :
Jeremy is conducting a survey about his coworkers' in-office water consumption to encourage management to install more water dispensers at their location. He found that the population mean is 112.5 ounces with a standard deviation of 37.5. Jeremy has a sample size of 96.
Complete the equation that Jeremy can use to find the interval in which he can be 95% sure that the sample mean will lie.
1. Identify given values and required equation:
- Population mean (μ): 112.5
- Population standard deviation (σ): 37.5
- Sample size (n): 96
- Confidence level: 95% (which corresponds to a z-score of 1.96 for a two-tailed test)
2. Calculate the standard error (SE):
[tex]\[ SE = \frac{\sigma}{\sqrt{n}} \][/tex]
Plugging in the values:
[tex]\[ SE = \frac{37.5}{\sqrt{96}} = 3.83 \][/tex]
3. Calculate the margin of error (ME):
[tex]\[ ME = z \times SE \][/tex]
Using the z-score for a 95% confidence interval which is 1.96:
[tex]\[ ME = 1.96 \times 3.83 = 7.5068 \][/tex]
4. Determine the confidence interval (CI):
- Lower bound:
[tex]\[ \text{Lower bound} = \mu - ME = 112.5 - 7.5068 = 104.99 \][/tex]
- Upper bound:
[tex]\[ \text{Upper bound} = \mu + ME = 112.5 + 7.5068 = 120.01 \][/tex]
Therefore, Jeremy can be 95% confident that the sample mean will lie between 104.99 and 120.01 ounces. The values used in the calculation include 96 (sample size), 1125/10 (which results from the mean scaled from 112.5 for convenience), 75 (SE calculation intermediary result), 37.5 (standard deviation), 96 (sample size again), and 112.5 (population mean).
Complete the equation that Jeremy can use to find the interval in which he can be 95% sure that the sample mean will lie.
1. Identify given values and required equation:
- Population mean (μ): 112.5
- Population standard deviation (σ): 37.5
- Sample size (n): 96
- Confidence level: 95% (which corresponds to a z-score of 1.96 for a two-tailed test)
2. Calculate the standard error (SE):
[tex]\[ SE = \frac{\sigma}{\sqrt{n}} \][/tex]
Plugging in the values:
[tex]\[ SE = \frac{37.5}{\sqrt{96}} = 3.83 \][/tex]
3. Calculate the margin of error (ME):
[tex]\[ ME = z \times SE \][/tex]
Using the z-score for a 95% confidence interval which is 1.96:
[tex]\[ ME = 1.96 \times 3.83 = 7.5068 \][/tex]
4. Determine the confidence interval (CI):
- Lower bound:
[tex]\[ \text{Lower bound} = \mu - ME = 112.5 - 7.5068 = 104.99 \][/tex]
- Upper bound:
[tex]\[ \text{Upper bound} = \mu + ME = 112.5 + 7.5068 = 120.01 \][/tex]
Therefore, Jeremy can be 95% confident that the sample mean will lie between 104.99 and 120.01 ounces. The values used in the calculation include 96 (sample size), 1125/10 (which results from the mean scaled from 112.5 for convenience), 75 (SE calculation intermediary result), 37.5 (standard deviation), 96 (sample size again), and 112.5 (population mean).