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In Exercises 9–12, test the claim about the difference between two population means μ1 and μ2 at the level of significance α. Assume the samples are random and independent, and the populations are
12. Claim: μ1 > μ2; α = 0.01, Assume
Sample statistics:
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Elementary Statistics: Picturing the World (7th Edition)
- Two samples were drawn independently from two normal populations. Sample 1: 11.6, 11.35, 10.1, 10.85, 10.35, 10.6, and 11.1.Sample 2: 5.85, 8.85, 9.85, 11.85 and 7.85.Test to determine whether the means of the two population differs (use α=0.05).arrow_forward6) Use a significance level of a = 0.05 to test the claim that µ # 32.6. The sample data from normal population consists of 15 scores for which x = 41.9 and s = 7.7.arrow_forward2. A U.S. government survey in 2007 said that the proportion of young Americans that earn a high school diploma is 0.87. a) Suppose you took a simple random sample of 100 young Americans. We know because of sampling variability that the sample proportion of those who earned a high school diploma would vary each time you took a sample. Assuming the value above can be taken as the population proportion (i.e., as a parameter), what model can be used to describe how these sample proportions would vary? Please be sure to include the name of the distribution and the parameter values. See pg. 131 in the Class Notes. b) Find the probability that 89% or more in the sample will have earned a high school diploma.arrow_forward
- Test the claim about the difference between two population means u, and u, at the level of significance a. Assume the samples are random and independent, and the populations are normally distributed. Claim: H, SHz; a = 0.10. Assume o, #o, Sample statistics: x, = 2418, s, = 179, n, = 15 and X2 = 2295, s, = 55, n, =9 Identify the null and alternative hypotheses. Choose the correct answer below. O A. Ho: H1> H2 Ha: H1 SH2 O B. Ho: H1 2H2 Ha: H1 H2 O D. Ho: H1arrow_forwardSuppose you have a sample of size n for variables X and Y. The sample covariance of X and Y is Cov(X,Y) = 1,000, the sample standard deviation for X is Sx=20 and the sample standard deviation for Y is SY=75. What is the sample correlation coefficient, r?arrow_forwardTest the claim about the difference between two population means H, and u2 at the level of significance a. Assume the samples are random and independent, and the populations are normally distributed. Claim: µ, SHzi a= 0.05. Assume o; *o, Sample statistics: X1 = 2417, s, = 177, n, = 12 and X2 = 2296, s2 = 55, n2 = 11 O A. Ho: H1 * H2 ZH = ht:"H 대>H :"H Find the standardized test statistic t. (Round to two decimal places as needed.) Find the P-value. (Round to three decimal places as needed.) Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim. V Ho. There V enough evidence at the 5% level of significance to reject the claim.arrow_forwardTest the claim about the difference between two population means H, and u2 at the level of significance a. Assume the samples are random and independent, and the populations are normally distributed. Claim: 41 SH2; a = 0.10. Assume o, #o, Sample statistics: X, = 2417, s, = 179, n, = 12 and X2 = 2296, s2 = 53, n2 = 10 Identify the null and alternative hypotheses. Choose the correct answer below. 대= 내 : "H OF. Ho: H1 2H2 Find the standardized test statistic t. (Round to two decimal places as needed.) Find the P-value. (Round to three decimal places as needed.) Decide whether to reject or fail to reject the null hypothesis and interpret the decision in the context of the original claim. V Ho. There V enough evidence at the 10% level of significance to reject the claim.arrow_forwardAn ecologist records the hourly number of birds x; (i = 1,2,3,...,40) flying over a wetland. The data summaries are 40 40 Σx, = 1200 and Σx² = 285 000. i=1 i=1 ii Based on past records, the number of the population mean of birds flying over the wetland in an hour is 34. Estimate the probability that the sample mean number of birds for 40 hours (1) is greater than 40, (2) is between 25 and the sample mean.arrow_forwardSuppose a hypertension trial is mounted and 18 participants are randomly assigned to one of three comparison treatments. Each participant takes the assigned medication and his or her systolic blood pressure is recorded after 6 months on the assigned treatment. The data are shown in Table 7–58. Is there a difference in mean systolic blood pressure among treatments? Run the appropriate test at α = 0.05. TABLE 7–58 Systolic Blood Pressure by Treatment Standard Treatment Placebo New Treatment 124 134 114 111 143 117 133 148 121 125 142 124 128 150 122 115 160 128arrow_forwardA statistician wants to determine if there is a difference in the fuel efficiency of cars between model years. To do this, he selects random makes and models of cars and compares the fuel efficiency in miles per gallon of the current model year and the previous model year. Suppose that data were collected for a random sample of 9 cars, where each difference is calculated by subtracting the fuel efficiency in miles per gallon of the previous model year from the fuel efficiency in miles per gallon of the current model year. Assume that the fuel efficiencies are normally distributed. What type of test is this hypothesis test? A. This is a two-tailed test because the alternative hypothesis is Ha:μd≠0. B. This is a right-tailed test because the alternative hypothesis is Ha:μd>0. C. This is a right-tailed test because the alternative hypothesis is Ha:μd<0. D. This is a left-tailed test because the alternative hypothesis is Ha:μd<0. E. This is a left-tailed…arrow_forward6. Independent random samples were selected from two populations. The sample means, known population variance, and sample sizes are given in the following table: Population 1 Population 2 Sample mean 34 38 Population Variance 5 7 Sample size 40 46 Find a 90% confidence interval for estimating the difference in the population means (μ₁ −μ₂).arrow_forwardA sample of n = 10 scores has a mean of M = 3. What is ΣX for this sample?arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
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