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 80 students in the highest quartile of the distribution, the mean score was x = 178.70. Assume a population standard deviation of ? = 8.15. These students were all classified as high on their need for closure. Assume that the 80 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 2.1 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.)

A graduate student is interested in how viewing different types of scenes affects working memory. For his study, he selects a random sample of 36 adults. The subjects complete a series of working memory tests before and after walking in an urban setting. Before the walk, the mean score on the test of working memory was 9.1. After the walk, the mean score was 1.4 higher. The graduate student has no presupposed assumptions about how viewing different types of scenes affects working memory, so he formulates the null and alternative hypotheses as: H00 : μDD = 0 H11 : μDD ≠ 0 Assume that the data satisfy all of the required assumptions for a repeated-measures t test. The graduate student calculates the following statistics for his hypothesis test: Mean difference (MDD) 1.4 Estimated population standard deviation of the differences (s) 1.6 Estimated standard error of the mean differences (sMDMD) 0.2667 Degrees of freedom (df) 35 The t statistic 5.25 The critical values of t…

In a study examining the relationship between socioeconomic status (SES) and academic achievement among high school students, the researchers collected data on 500 students from varying SES backgrounds. The SES was categorized into low, medium, and high. The academic achievement was measured using GPA scores. The following descriptive statistics were obtained: Mean GPA for low SES students: 2.8 Standard deviation of GPA for low SES students: 0.5 Mean GPA for medium SES students: 3.5 Standard deviation of GPA for medium SES students: 0.3 Mean GPA for high SES students: 4.0 Standard deviation of GPA for high SES students: 0.2 a) Calculate the coefficient of variation for each SES group and interpret the results.

A survey was conducted where 27 students were asked which social media app is their favorite, Twitter or Tiktok.    male female twitter 4 4 TikTok 4 15  create and interpret (in context) a one-proportion confidence interval. You may choose the level of confidence. conduct a Chi-Squared test for Association to determine if your data provide statistically significant evidence of an association between your two variables.

4. At private college the achievement test is used for advanced study placement. Counselors selected a random sample of 144 students from the college and scored their tests by hand before sending them in for computer processing. For this sample, the mean was 450 and s = 29. Construct a 98% confidence interval for the mean.

Three students, Linda, Tuan, and Javier, are given five laboratory rats each for a nutritional experiment. Each rat's weight is recorded in grams. Linda feeds her rats Formula A, Tuan feeds his rats Formula B, and Javier feeds his rats Formula C. At the end of a specified time period, each rat is weighed again, and the net gain in grams is recorded. Using a significance level of 10%, test the hypothesis that the three formulas produce the same mean weight gain. (Let 1 = Linda's rats, 2 = Tuan's rats and 3 = Javier's rats.) Weights of Student Lab Rats Linda's rats Tuan's rats Javier's rats 43.0 46.9 51.1 38.5 40.1 40.4 40.7 38.4 37.1 45.8 45.7 44.8 37.8 43.6 47.7 Part (a) State the null hypothesis. H0: ?1 = ?2 = ?3 H0: At least two of the group means ?1, ?2, ?3 are not equal.      Part (b) State the alternative hypothesis. Ha: ?1 = ?2 = ?3 Ha: At least two of the group means ?1, ?2, ?3 are not equal.      Part (c) Enter an exact number as an…

According to a recent article about individuals who have credit cards, the mean number of cards per person with credit cards is 4.5. To test this result a random survey of 60 individuals who have credit cards was conducted. The survey only includes the number of credit cards per participant. The results of the survey are attached below. (a) What is the variable of interest in this study? Is it qualitative or quantitative? (b) Do the results of the survey imply that the mean number of cards per individual is less than 4.5? Use the a = 0.05 level of significance. E Click the icon to view the data from the survey. (a) What is the variable of interest in this study? Is it qualitative or quantitative? The variable of interest is number of credit cards.It is a quantitative variable. (b) Do the results of the survey imply that the mean number of cards per individual is less than 4.5? Use the a = 0.05 level of significance. State the null and alternative hypotheses. Họ: H = 4.5 < 4.5 H1: H…

A cruise ship charges passengers $3 for a can of soda. Because of passenger complaints, the ship manager has decided to try out a plan with a lower price. He thinks that with a lower price, more cans will be sold, which would mean that the ship would still make a reasonable total profit. With the old pricing, the mean number of cans sold per passenger for a 10-day trip was 10.3 cans. Suppose μ represents the mean number of cans per passenger for the new pricing. What hypotheses should the ship manager test if he wants to determine if the mean number of cans sold is greater for the new pricing plan? O Ho: μ = 10.3 versus H₂: μ> 10.3 O Ho: μ = O Ho: μ = 10 versus Ha: μ 10.3

At one large college, 660 out of the 1500 students surveyed said they plan to take another science class.Find the 95% confidence interval for the proportion of students that said they plan to take another science class.

The Survey of Study Habits and Attitudes (SSHA) is a psychological test that measures students' study habits and attitudes toward school. The survey yields several scores, one of which measures student attitudes toward studying. The mean student attitude score for college students is about 30, and standard deviation is about 12. A researcher in the Philippines is concerned about the declining performance of college graduates on professional licensure and board exams. She suspects that poor attitudes of students are partly responsible for the decline and that the mean for college seniors who plan to take professional licensure or board exams is less than 30. She gives the SSHA to an SRS of 144 college seniors in the Philippines who plan to take professional licensure or board exams. Suppose we know that the student attitude scores in the population of such students are Normally distributed with standard deviation σ = 12. (a) We seek evidence against the claim that μ = 30. What is the…