Math Problem Statement

You believe the population is normally distributed, but you do not know the standard deviation. You obtain the following sample of data: 83.7, 65.2, 111, 80, 96.7, 75.3. The hypothesis being tested is H0: μ = 78.1 vs Ha: μ > 78.1. Calculate the test statistic and p-value. Determine whether to reject or fail to reject the null hypothesis and state the conclusion.

Solution

Based on the uploaded image, we are working with a hypothesis testing problem. Let's analyze and calculate step by step:

Hypothesis:

  • Null Hypothesis (H0H_0): μ=78.1\mu = 78.1
  • Alternative Hypothesis (HaH_a): μ>78.1\mu > 78.1

This is a one-tailed test, and we are testing whether the population mean is greater than 78.1.

Data provided:

Sample data: 83.7, 65.2, 111, 80, 96.7, 75.3

You are asked to calculate:

  1. Test statistic (accurate to three decimal places)
  2. p-value (accurate to four decimal places)

Step 1: Calculate the sample mean (xˉ\bar{x}) and standard deviation (ss):

To calculate these: xˉ=Sum of all sample valuesNumber of values\bar{x} = \frac{\text{Sum of all sample values}}{\text{Number of values}} s=(xixˉ)2n1s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n-1}}

Step 2: Compute the t-test statistic:

The formula for the t-test statistic is: t=xˉμs/nt = \frac{\bar{x} - \mu}{s / \sqrt{n}} Where:

  • xˉ\bar{x} = sample mean
  • μ=78.1\mu = 78.1 = hypothesized mean
  • ss = sample standard deviation
  • n=6n = 6 = sample size

Step 3: Find the p-value:

Using the t-test statistic and degrees of freedom (df=n1=5df = n-1 = 5), calculate the one-tailed p-value.

Let me calculate this for you.import numpy as np from scipy.stats import t

Given data

data = np.array([83.7, 65.2, 111, 80, 96.7, 75.3]) mu = 78.1 # Hypothesized mean n = len(data) # Sample size

Step 1: Calculate sample mean and standard deviation

sample_mean = np.mean(data) sample_std = np.std(data, ddof=1) # Use ddof=1 for sample standard deviation

Step 2: Calculate the t-statistic

t_statistic = (sample_mean - mu) / (sample_std / np.sqrt(n))

Step 3: Calculate the p-value (one-tailed)

df = n - 1 # Degrees of freedom p_value = 1 - t.cdf(t_statistic, df)

(sample_mean, sample_std, t_statistic, p_value)(85.31666666666666, 16.279486068874125, 1.0858543631106046, 0.1635493256750673)(85.31666666666666, 16.279486068874125, 1.0858543631106046, 0.1635493256750673)successHere are the calculated results:

  1. Sample Mean (xˉ\bar{x}): 85.31785.317 (rounded to three decimal places)
  2. Sample Standard Deviation (ss): 16.27916.279 (rounded to three decimal places)
  3. Test Statistic (tt): 1.0861.086 (rounded to three decimal places)
  4. p-value: 0.16350.1635 (rounded to four decimal places)

Interpretation:

  • The p-value is 0.16350.1635, which is greater than the commonly used significance level (α=0.05\alpha = 0.05).
  • Thus, we fail to reject the null hypothesis. This means there is not enough evidence to conclude that the population mean is greater than 78.178.1.

Would you like a further breakdown or visualization of the calculations?

Related Questions:

  1. How is the t-distribution used in hypothesis testing?
  2. What happens to the p-value if the sample size increases?
  3. How does the standard deviation affect the t-test result?
  4. Can this test be performed using a z-test instead? Why or why not?
  5. What are the assumptions of the one-sample t-test?

Tip: Always confirm that your data meets the assumptions of normality when using a t-test for small sample sizes.

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Math Problem Analysis

Mathematical Concepts

Hypothesis Testing
One-sample t-test
P-values

Formulas

Sample mean: x̄ = Σx / n
Sample standard deviation: s = √[Σ(xi - x̄)² / (n-1)]
t-statistic: t = (x̄ - μ) / (s / √n)
P-value: Area under the t-distribution curve for given t and degrees of freedom

Theorems

t-distribution theorem
Central Limit Theorem

Suitable Grade Level

Undergraduate Statistics