Do students reduce study time in classes where they achieve a higher midterm score? In a Journal of Economic Education article (Winter 2005), Gregory Krohn and Catherine O’Connor studied student effort and performance in a class over a semester. In an intermediate macroeconomics course, they found that “students respond to higher midterm scores by reducing the number of hours they subsequently allocate to studying for the course.” Suppose that a random sample of n = 8 students who performed well on the midterm exam was taken and weekly study times before and after the exam were compared. The resulting data are given in Table 10.6. Assume that the population of all possible paired differences is normally distributed.

Table 10.6

Paired T-Test and CI: Study Before, Study After

95% CI for mean difference: (1.97112, 6.77888)

T-Test of mean difference = 0 (vs not = 0): T-Value = 4.30, P-Value = .0036

(a) Set up the null and alternative hypotheses to test whether there is a difference in the true mean study time before and after the midterm exam.

H₀: µ_d =  versus H_a: µ_d ?

(b) Above we present the MINITAB output for the paired differences test. Use the output and critical values to test the hypotheses at the .10, .05, and .01 level of significance. Has the true mean study time changed? (Round your answer to 2 decimal places.)

t =   We have (Click to select)novery strongextremely strongstrong evidence.

(c) Use the p-value to test the hypotheses at the .10, .05, and .01 level of significance. How much evidence is there against the null hypothesis?

There is (Click to select)very strong evidenceextermly strong evidencestrong evidenceno evidence against the null hypothesis.

Think about a population mean that you may be interested in and propose a hypothesis test problem for this parameter. Gather appropriate data and post your problem, Later, respond to your own post with your own solution. On a TI-83

My problem is:

I asked 10 teenagers how many times this monthnhave thely used a land line phone.

My results are as following: 2,0,1,1,0,0,3,0,1,0

I'd like to propose that the population mean for the amount of times that a teenager has used a land line phone in the past month is greater than 1 and I would like to test this hypothesis at a 0.01 significance level.

Red Bull is the most popular energy drink in sales in the United States. Red Bull GmbH (the parent company) has observed that daily sales are normally distributed with an average of 6,284,050 drinks sold with a standard deviation of 8,130.78. What is the probability that on a given day between 6,290,096 and 6,301,996 drinks are sold? Question 9 options: 1) We do not have enough information to calculate the value. 2) 0.0136 3) 0.2149 4) 0.0005 5) 0.7715

Question 10 (1 point) When students use the bus from their dorms, they have an average commute time of 11.13 minutes with standard deviation 3.0876 minutes. Approximately 26.34% of students reported a commute time less than how many minutes? Assume the distribution is approximately normal. Question 10 options: 1) 9.18 2) 13.08 3) 5.1 4) 17.16 5) We do not have enough information to calculate the value.

Question 11 (1 point) Suppose that the distribution of income in a certain tax bracket is approximately normal with a mean of $53,183.88 and a standard deviation of $1,799.608. Approximately 18.56% of households had an income greater than what dollar amount? Question 11 options: 1) We do not have enough information to calculate the value. 2) 54,793.14 3) 51,574.62 4) 2,842,851 5) 2,949,219

Question 12 (1 point) According to a survey conducted by Deloitte in 2017, 0.4609 of U.S. smartphone owners have made an effort to limit their phone use in the past. In a sample of 89 randomly selected U.S. smartphone owners, what is the probability that greater than 46 will have attempted to limit their cell phone use in the past? Question 12 options: 1) 0.0241 2) 0.1703 3) 0.8779 4) 0.0483 5) 0.1221

Question 13 (1 point) According to a survey conducted by Deloitte in 2017, 0.4702 of U.S. smartphone owners have made an effort to limit their phone use in the past. In a sample of 54 randomly selected U.S. smartphone owners, what is the probability that between 22 and 29 (inclusively) will have attempted to limit their cell phone use in the past? Question 13 options: 1) 0.1383 2) 0.7244 3) 0.2756 4) 1.0844 5) 0.0132

Question 14 (1 point) According to a survey conducted by Deloitte in 2017, 0.44 of U.S. smartphone owners have made an effort to limit their phone use in the past. In a sample of 87 randomly selected U.S. smartphone owners, approximately __________ owners, give or take __________, will have attempted to limit their cell phone use in the past. Assume each pick is independent. Question 14 options: 1) 4.63 , 38.28 2) 38.28 , 21.40 3) 87 , 4.63 4) 38.28 , 0.44 5) 38.28 , 4.63

For the decision problem in Figure 6.1, use data tables to perform the following sensitivity analyses. The goal in each is to see whether decision 1 continues to have the largest EMV. In each part, provide a brief explanation of the results.

a. Let the payoff from the best outcome, the value in cell A3, vary from $30,000 to $50,000 in increments of $2500.

b. Let the probability of the worst outcome for the first decision, the value in cell B5, vary from 0.7 to 0.9 in increments of 0.025, and use formulas in cells B3 and B4 to ensure that they remain in the ratio 1 to 2 and the three probabilities for decision 1 continue to sum to 1.

c. Use a two-way data table to let the inputs in parts a and b vary simultaneously over the indicated ranges.

Please provide solution as per Excel.

An article in Information Security Technical Report [“Malicious Software—Past, Present and Future” (2004, Vol. 9, pp. 6–18)] provided the following data on the top 10 malicious software instances for 2002. The clear leader in the number of registered incidences for the year 2002 was the Internet worm “Klez,” and it is still one of the most widespread threats. This virus was first detected on 26 October 2001, and it has held the top spot among malicious software for the longest period in the history of virology.

The 10 most widespread malicious programs for 2002

(Source: Kaspersky Labs).

Suppose that 20 malicious software instances are reported. Assume that the malicious sources can be assumed to be independent. (a) What is the probability that at least one instance is “Klez?” (b) What is the probability that three or more instances are “Klez?” (c) What are the mean and standard deviation of the number of “Klez” instances among the 20 reported?

IQ is normally distributed with a mean of 100 and a standard deviation of 15. Suppose an individual is randomly chosen. a) Find the probability that the person has an IQ greater than 125. b) Find the probability that the person has an IQ score between 105 and 118. c) What is the IQ score of a person whose percentile rank is at the 75th percentile, ?75? d) Use the information from part (c) to fill in the blanks and circle the correct choice in the following statement. ________% of the individuals (persons) have IQ score less than/more than __________ e) “MENSA” is an organization whose members have the top 2% of all IQs. Find the minimum IQ needed to qualify for the “MENSA” organization.

Propose the following items for a pseudo-study: E-Learning

1. Research Question- Is E-Learning a useful education tool for adult learners
2. Hypotheses:
3. Null and Research
4. Variables (independent and dependent)
5. Levels of Measurement
6. Sample Population
7. Sample Size
8. Descriptive Statistics

8. The mean number of fatal accidents between Mile markers 0 and 40 is 5 per year.

What is the probability there are a) exactly 3 fatalities b) less than 5 fatalities, c) 4 or less fatalities d) greater than 4 fatalities, greater e) Between 1 and 4 fatalities (10 points)

4.40 Two children.

Each of us has an ABO blood type, which describes whether two characteristic, called A and B, are present. Every one of us has two blood type alleles (gene forms), one inherited from our mother and one from our father. Each of these alleles can be A, B, or O. Which two we inherit determines our blood type. Here is a table that shows what our blood type is for each combination of two inherited alleles:

We inherit each of a parent's two alleles with probability 0.5. We inherit independently from our mother and father.

Samantha has alleles B and O. Dylan has alleles A and B. They have two children.

What is the probability that both children have blood type A? (report to 4 decimal places as a proportion) ________________________

What is the probability that both children will have the same blood type? (report to 3 decimal places as a proportion) _________________

1 point) Independent random samples, each containing 60 observations, were selected from two populations. The samples from populations 1 and 2 produced 33 and 22 successes, respectively. Test H0:(p1−p2)=0 against Ha:(p1−p2)≠0. Use α=0.08.

(a) The test statistic is____

(b) The P-value is ____

(c) The final conclusion is A. We can reject the null hypothesis that (p1−p2)=0 and accept that (p1−p2)≠0. B. There is not sufficient evidence to reject the null hypothesis that (p1−p2)=0.

A shopkeeper hires vacuum cleaners to the general public at 5$ per day. The mean daily demand is 2.6. Suppose the demand follows Poisson distribution. (a) Calculate the expected daily income from this activity assuming an unlimited number of vacuum cleaners is available (b) Find the probability that the demand on a particular day is: 0, exactly 1, exactly 2, exactly 3 or more than 3; (c) If only 3 vacuum cleaners are available for hire calculate the mean of the daily income. A nearby large store is willing to lend vacuum cleaners at short notice to the shopkeeper, so that she is able to meet the demand. However, this shop will charge £2 per day for this service regardless of how many, if any, cleaners are borrowed. Would you advice the shopkeeper to take this offer?

Russia has recently started a push for stronger smoking regulations much like those in Western countries concerning cigarette advertising, smoking in public places, and so on. Listed below is sample data on smoking habits of Russians that are consistent with those Analyze the data and answer the following questions.

Develop a point estimate and a 95% confidence interval for the proportion of Russians who smoke.

Develop a point estimate and a 95% confidence interval for the mean annual per capita consumption (number of cigarettes) of a Russian.

For those Russians who do smoke, estimate the number of cigarettes smoked per day.

2a) Calculate an average and sample standard deviation for the independent variable (time of heating) and the dependent variable (number of surviving organisms) given the data in the table below.

Time (min) ... Number of Survivors

0.1 ...    2.01x10^6

7.5 ... 2.95x10^5

15 ...    8.42x10^4

22.5 ... 2.43x10^4

30 ... 6.99x10^3

2 b) Plot the number of survivors over tie on Cartesian, semi-log and log-log axes using only the data points. Identify the plot that best presents the data. Explain why this plot is better. Add a trend line that presents the data, including an R^2 value and equation.

2 c) Using the prediction equation developed in 2b, estimate the number of survivors after heating for 50 minutes. How confident is this estimate? Why?

A researcher was interested in the anxiety present in students just prior to the midterm exam. The research used an anxiety self-quiz to gage the student's anxiety. The score for 30 students are: 69,61,84,99.66.86.91.94,54,66,77,48, 70,70,86,98.56,43,70,88,78,53,85, 40,86,79,58,40,89,70. 1. Construct a frequency table with class, frequency, relative percent and cumulative percent that has 6 classes to describe the distribution of the data. 2. Use the frequency table to construct a histogram. 3. Calculate the numerical descriptive statistics mean, median, standard deviation, and variance of the anxiety scores. Please show all work.

Use the following information to answer the next 3 questions. Parents of children with developmental disorders can apply for federal funding, to help pay for psychosocial rehabilitation. A sociologist working for the annual Current Population Survey wants to know the percentage of applicants for this funding who are in poverty. She needs a sample of applicants from across the U.S., so she groups all of the applications by state and randomly selects applicants from each state. She calculates the percentage of applicants in her sample that are in poverty. Is this percentage a parameter or a statistic, and why?