Researchers conducted an experiment to test the effects of alcohol. Errors were recorded in a test of visual and motor skills for a treatment group of 21 people who drank ethanol and another group of 21 people given a placebo. The errors for the treatment group have a standard deviation of 2.10, and the errors for the placebo group have a standard deviation of 0.71. Use a 0.05 significance level to test the claim that the treatment group has errors that vary significantly more than the errors of the placebo group. Assume that the two populations are normally distributed.

Researchers conducted an experiment to test the effects of alcohol. Errors were recorded in a test of visual and motor skills for a treatment group of 22 people who drank ethanol and another group of 22 people given a placebo. The errors for the treatment group have a standard deviation of 2.30​, and the errors for the placebo group have a standard deviation of 0.74. Use a 0.05 significance level to test the claim that the treatment group has errors that vary significantly more than the errors of the placebo group. Assume that the two populations are normally distributed. => Identify the test statistic.   (Round to two decimal places as​ needed.)   Use technology to identify the​ P-value.   ​(Round to three decimal places as​ needed.)   What is the conclusion for this hypothesis​ test?   reject/fail to reject?

The National Collegiate Athletic Association (NCAA) requires Division I athletes to score at least 813 on the combined mathematics and verbal parts of the SAT exam to compete in their first college year. (Higher scores are required for students with poor high school grades.) In 2012, the scores of the 2.6 million students taking the SATs were approximately Normal with mean 1020 and standard deviation 207. What percent of all students had scores less than 813?

In a test of the effectiveness of garlic for lowering​ cholesterol, 36subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes​ (before minus​ after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 0.9and a standard deviation of 2.28. Use a 0.05 significance level to test the claim that with garlic​ treatment, the mean change in LDL cholesterol is greater than 0.What do the results suggest about the effectiveness of the garlic​ treatment? Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.   a) What are the null and alternative​ hypotheses? b) Determine the test statistic. c) Determine the​ P-value. d) (reject/do not reject). There is (sufficient/not sufficient) evidence to conclude that the mean of the population of changes are (=, not, >, <) to 0.

Researchers conducted an experiment to test the effects of alcohol. Errors were recorded in a test of visual and motor skills for a treatment group of 21 people who drank ethanol and another group of 21 people given a placebo. The errors for the treatment group have a standard deviation of 2.40​, and the errors for the placebo group have a standard deviation of 0.83. Use a 0.05 significance level to test the claim that the treatment group has errors that vary significantly more than the errors of the placebo group. Assume that the two populations are normally distributed. What are the null and alternative​ hypotheses? A. Ho​: σ 1 2 ≠ σ 2 2     H1​:σ 1 2= σ 2 2 B. Ho​: σ 1 2= σ 2 2     H1: σ 1 2> σ 2 2 C. Ho​: σ 1 2= σ 2 2      H1​: σ 1 2< σ 2 2 D. Ho​: σ 1 2= σ 2 2       H1: σ 1 2≠ σ 2 2 Identify the test statistic. ________________​ (Round to two decimal places as​ needed.) Use technology to identify the​ P-value. ______________ ​(Round to three decimal places as​ needed.) What…

Two competing headache remedies claim to give fast-acting relief. An experiment was performed to compare the mean lengths of time required for bodily absorption of brand A and brand B headache remedies. Twelve people were randomly selected and given an oral dosage of brand A. Another 12 were randomly selected and given an equal dosage of brand B. The lengths of time in minutes for the drugs to reach a specified level in the blood were recorded. The means, standard deviations, and sizes of the two samples follow. Sample standard deviation 8.7 min Brand Sample size Sample mean A 12 21.8 min B 12 18.9 min 7.5 min Past experience with the drug composition of the two remedies permits researchers to assume that both distributions are approximately normal with equal variances. Let us use a 5% level of significance to test the claim that there is no difference in the mean time required for bodily absorption. Also, find or estimate the p – value of the sample test statistic.

In a study, a random sample of 20 adults rated the effectiveness of advertisements. Each adult rated an advertisement that lasted 30 or 60 seconds. The block design in the accompanying table shows these ratings (on a scale of 1 to 5, with 5 being extremely effective). Use a = 0.05 and a technology tool and the given block design to perform a two-way ANOVA test. Click the icon to view the block design and ratings. Determine the null and alternative hypotheses for the main effects. Select all that apply. O A. Ho: The length of the ad has no effect on the rating. B. Ho: The rating has no effect on the advertising medium. Ha: The rating has an effect on the advertising medium. Ha: The length of the ad has an effect on the rating. O c. Ho: The advertising medium has no effect on the rating. D. Ho: : The advertising medium has no effect on the length of the ad. Ha: The advertising medium has an effect on the rating. : The advertising medium has an effect on the length of the ad. Ha: length…

The Graded Naming Test (GNT) is used when diagnosing cognitive deficits of the sort that can occur after astroke or closed-head injury. The GNT was developed by British researchers and tens of thousands of people inBritain have taken it; the mean score is 20.4 and the standard deviation is 17.5. Canadian researchers suspect thatCanadians (who don’t speak British English) will score lower than the Brits. A sample of 30 Canadians who took theGNT scored 18.73, on average. Identify/calculate the mean and standard deviation of themeans of the samples. Draw and Label the distribution. Identify the critical value(s) for this test, label it (them) on the distribution, shade the rejection region(s). Calculate the test statistic, mark and label it on the comparison distribution.State the hypothesis-testing conclusion, in words in terms of this test.

In a test of the effectiveness of garlic for lowering​ cholesterol, 36 subjects were treated with raw garlic. Cholesterol levels were measured before and after the treatment. The changes​ (before minus​ after) in their levels of LDL cholesterol​ (in mg/dL) have a mean of 0.6 and a standard deviation of 1.54. Use a 0.10 significance level to test the claim that with garlic​ treatment, the mean change in LDL cholesterol is greater than 0. What do the results suggest about the effectiveness of the garlic​ treatment? Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.

An experiment was conducted on rodents to determine if the drug Haldol influenced the amount of "rough play." Five groups were included in the experiment. Subsequent behavior in terms of mean "rough play" behaviors was recorded. The output and box plot below, display the mean differences from baseline (i.e., after the drug was administered compared to before drug administration). What are the null and alternative hypotheses of this test? Summary of Roughplay differences Scd. Dev. Haldol dese Mean Freq. -.63158419 13.290618 19 Vehicle | 0.025 mg i 0.05 mg/ 1 0.1 mg/k -12.754389 13.783537 0.2 mg/k I 18 1.1481501 20.447041 5.0499951 16.035879 20 19 -20.S5 16.431064 20 Total -5.6631968 1B.558994 96 Analysis of Variance Frob F (p-value) Source SS df KS F Test- Statistic 8999.32832 4 2249.33203 9.63 0.0000 Between groups Within groups 91 260.682623 23722.1178 Tozal 32721.4461 95 344.436275 chif (4) 4.1710 Prob>chiz = 0.303 = Bartlett's test for equal variances: Roeghpiay diferences -50 Ho: 0…