Math Problem Statement

You wish to test the following claim (Ha) at a significance level of α=0.05.

Ho:μ=75.2 Ha:μ≠75.2

You believe the population is normally distributed, but you do not know the standard deviation. You obtain the following sample of data:

data

66

75.1

69.2

67

70.5

77.1

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? (Report answer accurate to four decimal places.) p-value =

The p-value is...

less than (or equal to) α

greater than α

This test statistic leads to a decision to...

reject the null

accept the null

fail to reject the null

As such, the final conclusion is that...

There is sufficient evidence to warrant rejection of the claim that the population mean is not equal to 75.2.

There is not sufficient evidence to warrant rejection of the claim that the population mean is not equal to 75.2.

The sample data support the claim that the population mean is not equal to 75.2.

There is not sufficient sample evidence to support the claim that the population mean is not equal to 75.2.

Solution

To perform the hypothesis test, we first need to calculate the sample mean and sample standard deviation from the provided data. Then we can compute the test statistic and the p-value.

Given Data:

  • Sample dataTo perform the hypothesis test, we first need to calculate the sample mean and sample standard deviation from the provided data. Then we can compute the test statistic and the p-value.

Given Data:

  • Sample 66, 75.1, 69.2, 67, 70.5, 77.1

Step 1: Calculate Sample Mean ( xˉ\bar{x} )

xˉ=66+75.1+69.2+67+70.5+77.16=425.9670.9833\bar{x} = \frac{66 + 75.1 + 69.2 + 67 + 70.5 + 77.1}{6} = \frac{425.9}{6} \approx 70.9833

Step 2: Calculate Sample Standard Deviation ( ss )

s=(xixˉ)2n1s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n - 1}} Where nn is the sample size (6).

  1. Calculate the squared deviations:

    • (6670.9833)224.0314(66 - 70.9833)^2 \approx 24.0314
    • (75.170.9833)216.7068(75.1 - 70.9833)^2 \approx 16.7068
    • (69.270.9833)23.1628(69.2 - 70.9833)^2 \approx 3.1628
    • (6770.9833)216.0914(67 - 70.9833)^2 \approx 16.0914
    • (70.570.9833)20.2339(70.5 - 70.9833)^2 \approx 0.2339
    • (77.170.9833)237.2490(77.1 - 70.9833)^2 \approx 37.2490
  2. Sum of squared deviations: 24.0314+16.7068+3.1628+16.0914+0.2339+37.249097.475324.0314 + 16.7068 + 3.1628 + 16.0914 + 0.2339 + 37.2490 \approx 97.4753

  3. Calculate ss: s=97.47536119.49514.4147s = \sqrt{\frac{97.4753}{6 - 1}} \approx \sqrt{19.4951} \approx 4.4147

Step 3: Calculate Test Statistic ( tt )

Using the formula for the t-test statistic: t=xˉμ0s/nt = \frac{\bar{x} - \mu_0}{s/\sqrt{n}} Where:

  • μ0=75.2\mu_0 = 75.2
  • n=6n = 6

t=70.983375.24.4147/64.21671.80492.337t = \frac{70.9833 - 75.2}{4.4147/\sqrt{6}} \approx \frac{-4.2167}{1.8049} \approx -2.337

Step 4: Calculate the p-value

For a two-tailed t-test with n1=5n - 1 = 5 degrees of freedom:

Using a t-table or calculator, we find the p-value corresponding to t2.337t \approx -2.337 and 5 degrees of freedom.

Using a t-distribution calculator:

  • p-value 0.0524\approx 0.0524

Conclusion

  1. Test Statistic: t2.337t \approx -2.337 (to three decimal places: -2.337)
  2. p-value: 0.0524\approx 0.0524 (to four decimal places: 0.0524)

Decision:

  • The p-value (0.0524) is greater than α=0.05\alpha = 0.05.
  • Therefore, we fail to reject the null hypothesis.

Final Conclusion:

There is not sufficient evidence to warrant rejection of the claim that the population mean is not equal to 75.2.


If you have any questions or need further details, feel free to ask! Here are some follow-up questions to consider:

  1. How would the conclusion change if the significance level were set to 0.01?
  2. What assumptions must be satisfied for this test to be valid?
  3. How would increasing the sample size affect the test statistic and p-value?
  4. What is the power of this test?
  5. Can you explain the implications of failing to reject the null hypothesis in a practical context?

Tip: Always check the conditions for using the t-test, such as normality and independence of observations.

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Math Problem Analysis

Mathematical Concepts

Statistics
Hypothesis Testing
Normal Distribution

Formulas

Sample Mean (\bar{x})
Sample Standard Deviation (s)
Test Statistic (t) = (\bar{x} - \mu_0) / (s / \sqrt{n})

Theorems

Central Limit Theorem
t-Test for Mean

Suitable Grade Level

Grades 11-12