A researcher compares the effectiveness of two different instructional methods. A random sample of 78 students using Method 1 produces a testing average of 89.5 with a standard deviation of 16.8. A sample of 117 students using Method 2 produces a testing average of 55.9 with a standard deviation of 8.2. Construct a 99% confidence interval for the true difference in testing averages between the two methods. Round the endpoints of your interval to the nearest tenth if necessary. Show all work.

6. Suppose that you choose a student at random, and let the random variable “H” represent the student’s studying time (in hours) last week. Suppose that “H” has a uniform distribution on the interval (25, 35). If you randomly select 10 students and that each person’s studying time follows this same probability distribution, independently from person to person, determine the probability that at least two of the students studied for more than 32 hours last week.  

The times that college students spend studying per week have a distribution skewed to the right with a mean of 7.6 hours and a standard deviation of 2.6 hours. Find the probability that the mean time spent studying per week for a random sample of 45 college students would be

a. between 7.0 and 7.9 hours.

Round your answer to two decimal places.

P=____

b. less than 7.3 hours.

Round your answer to two decimal places.

P=____

Your public relations firm is awarded a $350,000 contract for a year-long program. The campaign objectives are threefold:

·     Encourage students and parents to consider college and take steps to apply.

·     Generate understanding that higher education is the key to a good job.

·     Convince students and parents to seek more information and visit the campus.

This campaign is not a “one size fits all” situation. What strategies and tactics would you do to effectively reach all of these under-represented groups?

SAT scores have a mean of 1000 and a standard deviation of 220.

Q18: What is the probability that a random student will score more than 1400?

Q19: Using the Central Limit Theorem, what is the probability that sample of 100 students will have an average score less than 990?

Q20: Using the Central Limit Theorem, what is the probability that sample of 100 students will have an average score between 990 and 1010?

Use excel functions to calculate your answers.

Describe three of the following perspectives regarding concept learning, and compare and contrast them regarding their usefulness in explaining how people acquire concepts:

                  • Prototypes

                  • Exemplars

                  • Buildup of associations

                  • Hypothesis testing

Describe at least three ways in which students in Piaget’s formal operations stage are likely to think differently from those in the concrete operations stage. Illustrate each characteristic with a concrete example of how students in each of the two stages might think or behave.

The state education commission wants to estimate the fraction of tenth grade students that have reading skills at or below the eighth grade level.

Step 2 of 2 :  

Suppose a sample of 801 tenth graders is drawn. Of the students sampled, 577 read above the eighth grade level. Using the data, construct the 95%confidence interval for the population proportion of tenth graders reading at or below the eighth grade level. Round your answers to three decimal places.

A university has 15,000 students. We have drawn a simple random sample size of 400 from the population and recorded how much money each student spent on cellular telephone service during November 2003. For this sample, the sample mean is $36, and sample standard deviation is $20. At a 99% level of confidence, test the null hypothesis that these 15,000 students, combined, did not spend more than $500,000 on cellular telephone service during November 2003.

Suggest one effective solution of each question and give some explanation or examples.

In a time-use study, 20 randomly selected college students were found to spend a mean of 1.4 hours on the internet each day. The standard deviation of the 20 scores was 1.3 hours.
Construct a 90% confidence interval for the mean time spent on the internet by college students. Assume t* = 1.729
If you increased the sample size for the problem above, what would happen to your confidence interval, assuming the sample mean and standard deviation remain unchanged?