Math Problem Statement

The postanesthesia care area (recovery room) at St. Luke's Hospital in Maumee, Ohio, was recently enlarged. The hope was that with the enlargement the mean number of patients per day would be more than 25. A random sample of 15 days revealed the following numbers of patients. 25 27 25 26 25 28 28 27 24 26 25 29 25 27 24. at the 0,01 significance level, can we conclude that the mean numberof patients per day is more than 25? estimate the p-value and interpret it

Solution

We will conduct a one-sample t-test to determine if the mean number of patients per day is significantly more than 25. The null hypothesis (H0H_0) and alternative hypothesis (HaH_a) are:

  • H0H_0: The mean number of patients per day is μ=25\mu = 25.
  • HaH_a: The mean number of patients per day is μ>25\mu > 25 (one-tailed test).

Steps:

  1. Sample Data: 25,27,25,26,25,28,28,27,24,26,25,29,25,27,2425, 27, 25, 26, 25, 28, 28, 27, 24, 26, 25, 29, 25, 27, 24

    • Sample size (nn) = 15
  2. Calculate the Sample Mean (xˉ\bar{x}): xˉ=Sum of all valuesn\bar{x} = \frac{\text{Sum of all values}}{n}

  3. Calculate the Sample Standard Deviation (ss): s=(xixˉ)2n1s = \sqrt{\frac{\sum{(x_i - \bar{x})^2}}{n-1}}

  4. Test Statistic (tt): t=xˉμs/nt = \frac{\bar{x} - \mu}{s / \sqrt{n}}

  5. Critical Value and p-value:

    • For α=0.01\alpha = 0.01, find the critical value from the t-distribution with n1n-1 degrees of freedom (df=151=14df = 15-1=14).
    • Compute the p-value.

Let’s calculate these values step by step.import numpy as np from scipy.stats import t

Sample data

data = [25, 27, 25, 26, 25, 28, 28, 27, 24, 26, 25, 29, 25, 27, 24] n = len(data) mu = 25 # Null hypothesis mean

Calculate sample mean

sample_mean = np.mean(data)

Calculate sample standard deviation

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

Calculate t-statistic

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

Degrees of freedom

df = n - 1

Calculate p-value for one-tailed test

p_value = 1 - t.cdf(t_statistic, df)

Critical t-value for alpha = 0.01

alpha = 0.01 critical_t = t.ppf(1 - alpha, df)

sample_mean, sample_std, t_statistic, critical_t, p_value(26.066666666666666, 1.533747356112131, 2.6935219933657377, 2.624494067560231, 0.008738459784443542)(26.066666666666666, 1.533747356112131, 2.6935219933657377, 2.624494067560231, 0.008738459784443542)success### Results:

  1. Sample Mean (xˉ\bar{x}): 26.0726.07
  2. Sample Standard Deviation (ss): 1.531.53
  3. Test Statistic (tt): 2.692.69
  4. Critical Value (tcriticalt_{critical}): 2.622.62 at α=0.01\alpha = 0.01 and df=14df = 14.
  5. p-value: 0.00870.0087

Conclusion:

  • Since t=2.69>tcritical=2.62t = 2.69 > t_{critical} = 2.62, we reject the null hypothesis (H0H_0).
  • The p-value (0.00870.0087) is less than the significance level (α=0.01\alpha = 0.01), indicating strong evidence that the mean number of patients per day is greater than 25.

Interpretation:

The enlargement of the recovery room appears to have significantly increased the mean number of patients per day, with a p-value of 0.00870.0087. This suggests that there is less than a 1% probability that this result is due to random chance under the null hypothesis.


Do you want further details on interpreting the t-test or visualizing the data?
Here are 5 related questions for exploration:

  1. How does sample size affect the t-test results?
  2. What is the difference between a one-tailed and two-tailed t-test?
  3. How is the critical value determined for different significance levels?
  4. What does the p-value indicate in hypothesis testing?
  5. Could we use a different test for similar data?

Tip: Always ensure that the sample data meets the assumptions of the t-test, including normality and independence.

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Math Problem Analysis

Mathematical Concepts

Hypothesis Testing
One-Sample t-Test
Statistical Significance

Formulas

Sample mean: \(\bar{x} = \frac{\text{Sum of all values}}{n}\)
Sample standard deviation: \(s = \sqrt{\frac{\sum{(x_i - \bar{x})^2}}{n-1}}\)
t-statistic: \(t = \frac{\bar{x} - \mu}{s / \sqrt{n}}\)

Theorems

Central Limit Theorem
t-Distribution Properties

Suitable Grade Level

Undergraduate (Statistics Course)