Math  /  Data & Statistics

QuestionShow how you arrived at your solution on the answer sheet for full credit. Write neatly and be organized. 8
PROBCEM 6 Weatherwise is a magazine published by the American Meteorological Society. One issue gives a rating system used lo classify Nor'easter storms that frequently hit New England and can cause much damage near the ocean. A severe storm has an average peak wave height of μ=16.4\mu=16.4 feet for waves hitting the shore. Suppose that a Nor'easter is in progress at the severe storm class rating. Peak wave heights are usually measured from land (using binoculars) off fixed cement piers. Suppose that a reading of 36 waves showed an average wave height of xˉ=17.3\bar{x}=17.3 feets. Previous studies of severe storms indicate that σ=3.5\sigma=3.5 feet. Does this information suggest that the storm is (perhaps temporarily) increasing above the severe rating?
Use the 0.01 level of significance and the P\mathbf{P} - Value method a.) Hypotheses (5 points): H0μ=16.4 feet Haμ>16.4 feet \begin{array}{l} H_{0} \cdot \mu=16.4 \text { feet } \\ H_{a} \cdot \mu>16.4 \text { feet } \end{array}
Levelot S Sandicance: α=0.01\alpha=0.01 Sample sie n=36n=36 z=0.93.5/6=0.90.58331.51nz=\frac{0.9}{3.5 / 6}=\frac{0.9}{0.5833} \approx 1.51 \sqrt{n} P(z>1.54)0.0618P(z>1.54) \approx 0.0618 d.) Decision ( 5 points):
Since the PP-value 0.0618 is greater than the sio level a=0.01a=0.01, we fail to reject the null hypo e.) Conclusion (5 points)

Studdy Solution

STEP 1

1. The null hypothesis H0:μ=16.4 H_0: \mu = 16.4 feet represents the average peak wave height for a severe storm.
2. The alternative hypothesis Ha:μ>16.4 H_a: \mu > 16.4 feet suggests the storm is increasing in severity.
3. The sample mean wave height is xˉ=17.3 \bar{x} = 17.3 feet.
4. The population standard deviation is σ=3.5 \sigma = 3.5 feet.
5. The sample size is n=36 n = 36 .
6. The significance level is α=0.01 \alpha = 0.01 .

STEP 2

1. State the hypotheses.
2. Calculate the test statistic.
3. Determine the P P -value.
4. Make a decision based on the P P -value.
5. Draw a conclusion.

STEP 3

State the null and alternative hypotheses:
\begin{align*} H_0: & \quad \mu = 16.4 \text{ feet} \\ H_a: & \quad \mu > 16.4 \text{ feet} \end{align*}

STEP 4

Calculate the test statistic using the formula for the z z -score:
z=xˉμσ/nz = \frac{\bar{x} - \mu}{\sigma / \sqrt{n}}
Substitute the given values:
z=17.316.43.5/36=0.93.5/6=0.90.58331.54z = \frac{17.3 - 16.4}{3.5 / \sqrt{36}} = \frac{0.9}{3.5 / 6} = \frac{0.9}{0.5833} \approx 1.54

STEP 5

Determine the P P -value for z>1.54 z > 1.54 :
Using standard normal distribution tables or a calculator, find:
P(z>1.54)0.0618P(z > 1.54) \approx 0.0618

STEP 6

Make a decision based on the P P -value:
Since the P P -value 0.0618 0.0618 is greater than the significance level α=0.01 \alpha = 0.01 , we fail to reject the null hypothesis.

STEP 7

Draw a conclusion:
There is not enough statistical evidence at the α=0.01 \alpha = 0.01 level to suggest that the storm is increasing above the severe rating.

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