8th Edition

ISBN: 8220106798706

Author: BRASE

Publisher: Cengage Learning US

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Chapter 9.1, Problem 23P

For Problems 19-24, please provide the following information.

(a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test?

(b) Check Requirements What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. Compute the z value of the sample test statistic.

(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level α ?

(e) Interpret your conclusion in the context of the application.

Insurance: Hail Damage Nationally, about 11 % of the total U.S. wheat crop is destroyed each year by hail (Reference: Agricultural Statistics, U.S. Department of Agriculture). An insurance company is studying wheat hail damage claims in Weld County. Colorado. A random sample of 16 claims in Weld County gave the following data (% wheat crop lost to hail).

15	8	9	II	12	20	14	11
7	10	24	20	13	9	12	5

The sample mean is x ¯ = 12.5 % . Let x be a random variable that represents the percentage of wheat crop in Weld County lost to hail. Assume that x has a normal distribution and σ = 5.0 % these data indicate that the percentage of wheat crop lost to hail in Weld County is different (either way) from the national mean of 11%? Use α = 0.01 .

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.

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Chapter 9.1, Problem 22P

Chapter 9.1, Problem 24P

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Chapter 9 Solutions

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Solution Summary: The author explains the level of significance, null hypothesis, and alternative hypothesis. The sampling distribution is normal and the sample test statistic is 1.20.

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