Students taking Professor’s Angela Mazza’s Introduction to Marketing course spent an average of 1.5 hours to complete an assignment with a standard deviation of 0.40 hours and it follows the normal probability distribution.

(a) Find the portion of the students who spent between 1.5 and 2.5 hours to complete an assignment.

(b) Find the portion of the students who spent more than 2.5 hours to complete an assignment.

(c) Find the portion of the students who spent between 2.5 and 2.7 hours to complete an assignment.

(d) Find the portion of the students who spent between 1 and 2.7 hours to complete an assignment.

A Maths quiz consists of 10 questions were given to a group of students. Each

question has 4 choices. Grade A is given to the students managed to get 70% marks

and above. According to the compiled data, 45% of students managed to get grade

A.

(a) What is the probability that exactly 3 of a random sample of 5 the students were

grade A?

(b) What is the probability that not more than 7 of a random sample of those 15

students were grade A?

(c) Among the candidates, one student has not studied and decided to guess the

answers to every questions. Find the probability that the candidate will get

grade A in the quiz.

Scores of students in a large Statistics class are normally distributed with a mean of 75 points and a standard deviation of 5 points.

1. Find the probability that a student scores more than 80 points
2. If 100 students are picked at random, how many do you expect to score below 70 points?
3. If top 10% of students obtain an A grade, how much should a student obtain to get an A grade.
4. Suppose four students are picked at random, find the probability that the average score of those four students is more than 80 points.

Please show all your work with explanation

The National Center for Education Statistics reported that 47% of college students work to pay for tuition and living expenses. Assume that a sample of 450 college students was used in the study.

a. Provide a 95 % confidence interval for the population proportion of college students who work to pay for tuition and living expenses. (to 2 decimals)

b. Provide a 99 % confidence interval for the population proportion of college students who work to pay for tuition and living expenses. (to 2 decimals)

  ,   

b. Provide a  confidence interval for the population proportion of college students who work to pay for tuition and living expenses. (to 2 decimals)

A university financial aid office polled a random sample of 839 male undergraduate students and 727 female undergraduate students. Each of the students was asked whether or not they were employed during the previous summer. 505 of the male students and 563 of the female students said that they had worked during the previous summer. Give a 90% confidence interval for the difference between the proportions of male and female students who were employed during the summer.

Step 1 of 3: Find the point estimate that should be used in constructing the confidence interval. Round your answer to three decimal places.

Step 2 of 3: Find the margin of error. Round your answer to six decimal places.

Step 3 of 3: Construct the 90% confidence interval. Round your answers to three decimal places.

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 83 students in the highest quartile of the distribution, the mean score was x = 176.10. Assume a population standard deviation of σ = 7.61. These students were all classified as high on their need for closure. Assume that the 83 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 μ on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.)

Here is the information for a class on campus. We need to randomly select two students to interview. (We don't want to interview the same student twice.) Class Frequency Freshman 21 Sophomore 14 Junior 9 Senior 6

(a) Are the two student selections going to be independent?

(b) What is the probability that we choose a Freshman and then a Senior?

(c) What is the probability that we choose a Sophomore and then another Sophomore?

(d) What is the probability that we choose a Freshman and a Senior in any order?

(e) What is the probability that both students are at the same class level?

(f) What is the probability that both students are not at the same class level?

(g) We decide we need to interview more students. We decide to interview a total of 6 randomly chosen students. What is the probability that all the students chosen are freshmen?

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 73 students in the highest quartile of the distribution, the mean score was x = 176.90. Assume a population standard deviation of σ = 7.65. These students were all classified as high on their need for closure. Assume that the 73 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 μ on the "need for closure scale" for all students with a high need for closure. (Round your answers to two decimal places.)