Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 67 students in the highest quartile of the distribution, the mean score was x = 175.90. Assume a population standard deviation of ? = 7.61. These students were all classified as high on their need for closure. Assume that the 67 students represent a random sample of all students who are classified as high on their need for closure. How large a sample is needed if we wish to be 99% confident that the sample mean score is within 2.4 points of the population mean score for students who are high on the need for closure? (Round your answer up to the nearest whole number.)  (       )students

A clinical psychologist is investigating the relationship between sleep and feelings ofanxiety. For a sample of 15 individuals, he asks each participant to indicate how many hours theytypically sleep each night and each participant also completes an anxiety assessment. The followingdata is obtained:Hours of sleep: M=6.0 SS=16.0Anxiety scores: M=8.0 SS=64.0SP = - 20.0 a. Compute the correlation between hours of sleep and anxiety scores.

According to the College Board, scores on the math section of the SAT Reasoning college entrance test for the class of 2010 had a mean of 516 and a standard deviation of 116. Assume that they are roughly normal.One of the quartiles of the scores from the math section of the SAT Reasoning test is 438. The other quartile is _______.

Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 65 students in the highest quartile of the distribution, the mean score was x = 175.10. Assume a population standard deviation of ? = 7.55. These students were all classified as high on their need for closure. Assume that the 65 students represent a random sample of all students who are classified as high on their need for closure. How large a sample is needed if we wish to be 99% confident that the sample mean score is within 1.5 points of the population mean score for students who are high on the need for closure? (Round your answer up to the nearest whole number.)students

A researcher gathered a sample of participants who volunteered for a studying of phobias. She measured anxiety level of participants as they viewed photos of spiders and again when they viewed puppies. Which statistical test is appropriate for this study and why?

Three experiments investigating the relation between need for cognitive closure and persuasion were performed. Part of the study involved administering a "need for closure scale" to a group of students enrolled in an introductory psychology course. The "need for closure scale" has scores ranging from 101 to 201. For the 75 students in the highest quartile of the distribution, the mean score was x = 176.90. Assume a population standard deviation of ? = 7.71. These students were all classified as high on their need for closure. Assume that the 75 students represent a random sample of all students who are classified as high on their need for closure. Find a 95% confidence interval for the population mean score ? on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.)

A pharmaceutical company needs to know if its new cholesterol drug, Praxor, is effective at lowering cholesterol levels. It believes that people who take Praxor will average a greater decrease in cholesterol level than people taking a placebo. After the experiment is complete, the researchers find that the 44 participants in the treatment group lowered their cholesterol levels by a mean of 18.7 points with a standard deviation of 3.3 points. The 39 participants in the control group lowered their cholesterol levels by a mean of 18.1 points with a standard deviation of 2.1 points. Assume that the population variances are not equal and test the company’s claim at the 0.02 level. Let the treatment group be Population 1 and let the control group be Population 2.   Step 1 of 3 :   State the null and alternative hypotheses for the test. Fill in the blank below. H0: μ1=μ2 Ha : μ1⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯μ2 Step 2 of 3: what is the test statistic Step 3 of 3: draw a conclusion, fail or reject. Is…

Logan and Brian began arguing about who did better on their tests, but they couldn't decide who did better given that they took different tests. Logan took a test in Art History and earned a 76.8, and Brian took a test in English and earned a 68.9. Use the fact that all the students' test grades in the Art History class had a mean of 71.9 and a standard deviation of 11.6, and all the students' test grades in English had a mean of 61 and a standard deviation of 9.4 to answer the following questions.a) Calculate the z-score for Logan's test grade.z=z= [Round your answer to two decimal places.] b) Calculate the z-score for Brian's test grade.z=z= [Round your answer to two decimal places.]c) Which person did relatively better? Logan Brian They did equally well.

A personnel psychologist has to decide which of three employees to place in a particular job that requires a high level of coordination. All three employees have taken tests of coordination, but each took a different test. Employee A scored 15 on a test with a mean of 10 and a standard deviation of 2; Employee B scored 350 on a test with a mean of 300 and a standard deviation of 40; and Employee C scored 108 on a test with a mean of 100 and a standard deviation of 16. (On all three tests, higher scores mean greater coordination.) Which employee has the best coordination?   (hint: convert raw scores to z scores and compare)   Select one: a. Employee A b. Employee B c. Employee C Clear my choice

A pharmaceutical company needs to know if its new cholesterol drug, Praxor, is effective at lowering cholesterol levels. It believes that people who take Praxor will average a greater decrease in cholesterol level than people taking a placebo. After the experiment is complete, the researchers find that the 46 participants in the treatment group lowered their cholesterol levels by a mean of 19.5 points with a standard deviation of 4.9 points. The 37 participants in the control group lowered their cholesterol levels by a mean of 18.4 points with a standard deviation of 4.1 points. Assume that the population variances are not equal and test the company's claim at the 0.02 level. Let the treatment group be Population 1 and let the control group be Population 2. Step 2 of 3: Compute the value of the test statistic. Round your answer to three decimal places.