Math Problem Statement
You believe the population is normally distributed, but you do not know the standard deviation. You obtain a sample of size n=14 with meanm=90.8 and a standard deviation of sd=10.6.
What is the test statistic for this sample? (Report answer accurate to three decimal places.) test statistic =
what is the p-value for this sample: right tailed
Solution
Since the population standard deviation is unknown, you need to use a t-test for the hypothesis. The formula for the t-test statistic is:
Where:
- (sample mean)
- = hypothesized population mean (typically 0 or whatever value is relevant)
- (sample standard deviation)
- (sample size)
If we assume (as is common when testing), the t-statistic becomes:
First, calculate the denominator:
Now, calculate the t-statistic:
So the t-statistic is:
Step 2: Calculate the p-value (right-tailed)
Since this is a right-tailed test, we need the p-value corresponding to the computed t-statistic with n - 1 = 13 degrees of freedom. You can find this using a t-distribution table or statistical software.
Using a t-table:
For t = 32.056 with 13 degrees of freedom, the p-value will be extremely small (near 0). In fact, for such a high t-value, the p-value is effectively:
This means the result is highly significant.
Would you like me to go into further details or check your specific hypothesis value?
Here are 5 related questions you may explore:
- How do you determine whether to use a t-test or z-test?
- What is the difference between one-tailed and two-tailed tests?
- How do degrees of freedom affect the shape of the t-distribution?
- What are Type I and Type II errors in hypothesis testing?
- How would the p-value change if it were a two-tailed test?
Tip: Always report your hypothesis and clearly before conducting tests for clarity and reproducibility.
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Math Problem Analysis
Mathematical Concepts
Statistics
Hypothesis Testing
T-Distribution
Right-Tailed Test
Formulas
t-test statistic formula: t = (X̄ - μ₀) / (s / √n)
Sample standard deviation calculation
Degrees of freedom: df = n - 1
Theorems
Central Limit Theorem
T-Distribution Theorem
Suitable Grade Level
College Undergraduate
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