Math Problem Statement

“ A researcher estimates that high school girls miss more days of school than high school boys. A sample of 16 girls showed that they missed an average of 3.9 days of school and a sample of 22 boys showed that they missed an average of 3.6 days. The standard deviation of the 16 girls was .6 and the standard deviation of the boys was .8. Using an alpha level of .01, test the researchers claim.” what is the P value

Solution

To determine the pp-value for this test, let's proceed with a hypothesis test comparing two means from independent samples, specifically focusing on whether high school girls miss more days of school than boys. We will use a one-tailed t-test for independent means.

Given dataTo determine the pp-value for this test, let's proceed with a hypothesis test comparing two means from independent samples, specifically focusing on whether high school girls miss more days of school than boys. We will use a one-tailed t-test for independent means.

Given

  • Sample size for girls (n1n_1) = 16

  • Mean for girls (xˉ1\bar{x}_1) = 3.9

  • Standard deviation for girls (s1s_1) = 0.6

  • Sample size for boys (n2n_2) = 22

  • Mean for boys (xˉ2\bar{x}_2) = 3.6

  • Standard deviation for boys (s2s_2) = 0.8

  • Significance level (α\alpha) = 0.01

Step 1: Set up the hypotheses

  • Null Hypothesis (H0H_0): μ1=μ2\mu_1 = \mu_2 (There is no difference in the average days missed between girls and boys).
  • Alternative Hypothesis (HaH_a): μ1>μ2\mu_1 > \mu_2 (Girls miss more days than boys).

Step 2: Calculate the test statistic

The test statistic for comparing two means with independent samples is given by: t=xˉ1xˉ2s12n1+s22n2t = \frac{\bar{x}_1 - \bar{x}_2}{\sqrt{\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}}}

Substituting the values:

  1. Difference in sample means: xˉ1xˉ2=3.93.6=0.3\bar{x}_1 - \bar{x}_2 = 3.9 - 3.6 = 0.3

  2. Standard error: s12n1+s22n2=0.6216+0.8222=0.3616+0.6422\sqrt{\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}} = \sqrt{\frac{0.6^2}{16} + \frac{0.8^2}{22}} = \sqrt{\frac{0.36}{16} + \frac{0.64}{22}} Calculating this gives: 0.0225+0.0291=0.05160.2272\sqrt{0.0225 + 0.0291} = \sqrt{0.0516} \approx 0.2272

  3. Test statistic tt: t=0.30.22721.32t = \frac{0.3}{0.2272} \approx 1.32

Step 3: Determine degrees of freedom

The degrees of freedom dfdf for this test can be approximated using the formula: df=(s12n1+s22n2)2(s12n1)2n11+(s22n2)2n21df = \frac{\left(\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}\right)^2}{\frac{\left(\frac{s_1^2}{n_1}\right)^2}{n_1 - 1} + \frac{\left(\frac{s_2^2}{n_2}\right)^2}{n_2 - 1}} Using this formula, we calculate df32df \approx 32 (approximately).

Step 4: Calculate the pp-value

Using a t-distribution table or calculator for a one-tailed test with t=1.32t = 1.32 and df32df \approx 32, we find that:

p0.097p \approx 0.097

Conclusion

With p=0.097p = 0.097 and α=0.01\alpha = 0.01, we fail to reject the null hypothesis because p>αp > \alpha. There is insufficient evidence to support the claim that high school girls miss more days than high school boys at the 1% significance level.


Would you like more details on any specific part of this calculation? Here are some related questions you might consider:

  1. What are the implications of failing to reject the null hypothesis?
  2. How would the conclusion change with a higher significance level, like 0.05?
  3. How is the degrees of freedom calculated, and why does it use the approximate method?
  4. What assumptions are required for a two-sample t-test to be valid?
  5. How could the sample size affect the reliability of this test?

Tip: When performing hypothesis tests, always verify if assumptions (like normality and independence) are met to ensure the results are valid.

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Math Problem Analysis

Mathematical Concepts

Hypothesis Testing
Inferential Statistics
t-Test for Independent Means

Formulas

t = (x̄1 - x̄2) / √((s1² / n1) + (s2² / n2))
Degrees of Freedom (df) for unequal variances

Theorems

Central Limit Theorem
Student's t-Distribution

Suitable Grade Level

College Level