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:

t=Xˉμ0s/nt = \frac{\bar{X} - \mu_0}{s / \sqrt{n}}

Where:

  • Xˉ=90.8\bar{X} = 90.8 (sample mean)
  • μ0\mu_0 = hypothesized population mean (typically 0 or whatever value is relevant)
  • s=10.6s = 10.6 (sample standard deviation)
  • n=14n = 14 (sample size)

If we assume μ0=0\mu_0 = 0 (as is common when testing), the t-statistic becomes:

t=90.8010.6/14t = \frac{90.8 - 0}{10.6 / \sqrt{14}}

First, calculate the denominator:

10.614=10.63.74172.833\frac{10.6}{\sqrt{14}} = \frac{10.6}{3.7417} \approx 2.833

Now, calculate the t-statistic:

t=90.82.83332.056t = \frac{90.8}{2.833} \approx 32.056

So the t-statistic is:

t=32.056t = 32.056

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:

p-value0.000\text{p-value} \approx 0.000

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:

  1. How do you determine whether to use a t-test or z-test?
  2. What is the difference between one-tailed and two-tailed tests?
  3. How do degrees of freedom affect the shape of the t-distribution?
  4. What are Type I and Type II errors in hypothesis testing?
  5. How would the p-value change if it were a two-tailed test?

Tip: Always report your hypothesis H0H_0 and H1H_1 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