A marketing director of a soft drink company wants to know what proportion of its potential U.S. customers have heard of a new brand. The company has access to a database with the mobile phone numbers of 10,000 U.S. college students. The director’s assistant asks a simple random sample of 50 students from this database whether they heard of the new soft drink brand, and constructs the sample proportion. 1 (a) What is the target population? (b) What is the sampled population? (c) Will the sample proportion be unbiased for the proportion in the sampled population? Explain. (d) Will the sample proportion be unbiased for the proportion in the target population? Explain.

The time needed to complete a final examination in a particular college course is normally distributed with a mean of 83 minutes and a standard deviation of 13 minutes. Answer the following questions.

a. What is the probability of completing the exam in one hour or less (to 4 decimals)?


b. What is the probability that a student will complete the exam in more than 60 minutes but less than 75 minutes (to 4 decimals)?


c. Assume that the class has 60 students and that the examination period is 90 minutes in length. How many students do you expect will be unable to complete the exam in the allotted time (to nearest whole number)?

identifying what statistical test is used? independent and dependent variable? complete analysis in JASP. Answer the research question, write  APA statement and Descriptive statistics.

A study by an American university examined whether scores on the SAT accurately predict students’ GPA score three semesters into their first year. A random sample of 11 students agreed to release their information for the purpose of the study.

Using the Binomial Distribution

Assume that two students must take a ten question, True or False quiz. Student 1 has not studied at all and guesses randomly on each question. Student 2 has studied hard and has a 95% chance of answering any particular question correctly.

For each student, calculate the probability of passing (getting 7 or more correct answers) and the probability of “acing” (getting 9 or 10 correct answers) the quiz.

What do your calculated probabilities say about the amount of preparation students do and their probability of doing well on the quiz?

Audio Co. Manages a chain of stores that sell audio systems. It has been very successful, but also many failures. The analysis of these failures has led it to adopt the policy of not opening a store unless they are reasonably sure that at least 15% of the students of the place have stereo systems with a cost of $ 1,100 or more. In a survey of 300 of the 2,400 students at a small arts school in the Midwest, he found that 57 of them had a stereo system that cost more than or equal to $ 1,100. If your company wants to run a 5% failure risk, should you open a store in this place?

Dr. Sammy Statsnerd surveyed her statistics students (N=60) to see if there was a relationship between the number of total courses the students were taking this semester and the level of stress that they felt about her statistics course. The results of the survey are below (30 points):

Assess the 3 properties of bivariate relationships and justify your answers.

1. Existence

2. Strength (use maximum difference)

3. Direction

The average American sees 15 movies per year. Jimmy believes that college students are different from the average American regarding movies. He gets a sample of four college students and asks them how many movies they see per year. They answer 2, 14, 2, 10. Do a t-test to see if Jimmy’s belief is true. Please calculate the t-statistic for this data. State the critical value, and come to a conclusion about Jimmy’s belief. Let α = .05. Make it a two-tailed test. Assume that it is okay to do a t-test.

Let's assume our class represents a normal population with a known mean of 90 and population standard deviation 2. There are 100 students in the class. a. Construct the 95% confidence interval for the population mean. b. Interpret what this means. c. A few students have come in. Now we cannot assume normality and we don't know the population standard deviation. Let the sample mean = 90 and sample standard deviation = 3. Let's make the sample size 20. We can assume alpha to be .05. Construct the 95% confidence interval assuming this new information

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Q25.If the records show that, the probability of failing (with grade F) this course is p, what is the probability that at most 2 students out of 15 fail this course? {Hint: use binomial distribution}

Q26.If the records show that, the probability for a student to get a grade B this course is p, what is the probability that exactly 4 students out of 15 will have a grade B for the course? {Hint: use binomial distribution}

Q27.What is the probability of selecting a grade A student for the first time either in 2nd or 3rd selection?

DATA: A:11 B:2 C:1 D:0 F:1

An SAT prep course claims to improve the test scores of students. The table shows the critical reading scores for 10 students the first two times they took the SAT, once before for the course, and once after the course. Test the company’s claim at α = 0.01. Extra columns provided for calculations.
Student Score
Before
Score After 1 308 400 2 456 524 3 352 409 4 433 491 5 306 348 6 471 583 7 422 451 8 370 408 9 320 391 10 418 450