A random sample of drug addicts in Seattle participated in a program to reduce drug dependency. Time 1 is a measure of the number of illegal drugs they took per day before participating in the program. Time 2 is a measure of the number of illegal drugs they took after participating in the program. You have been hired to evaluate the success of the program. You hypothesize that the average number of illegal drugs consumed by the addicts after participating in the program will decrease compared to the average number of illegal drugs consumed prior to participating in the program. Below are the data.
Interpret your answer using an alpha of .05.
|
Time 1 (drugs taken before program) |
Time 2 (drugs taken after participating in the program) |
Difference |
D2 |
|
2.00 |
1.00 |
-1 |
1 |
|
3.00 |
4.00 |
1 |
1 |
|
3.00 |
3.00 |
0 |
0 |
|
4.00 |
5.00 |
1 |
1 |
|
4.00 |
3.00 |
-1 |
1 |
|
5.00 |
3.00 |
-2 |
4 |
|
Sum = 21 |
Sum = 19 |
Sum = -2 |
Sum = 8 |
|
Mean = 3.5 |
Mean = 3.17 |
Mean = -.33 |
Mean = 1.33 |
| a. |
The obtained value does exceed the critical value of 2.015 at the .05 level of significance. The null hypothesis must not be accepted and it can be concluded that there is a significant difference between the two sets of scores and hence the program is successful. |
|
| b. |
The obtained value does not exceed the critical value of 2.015 at the .05 level of significance. The null hypothesis must be accepted and it can be concluded that there is no significant difference between the two sets of scores and hence the program is not successful. |
|
| c. |
No interpretation is needed since .67 is greater than .05. |
In: Statistics and Probability
Studying dose response is central to determining ”safe” and ”hazardous” levels and dosages for potential pollutants. These conclusions are often the basis for environmental policy. The U.S. Environmental Protection Agency has developed extensive guidance and reports on dose-response modeling and assessment. In this problem, we study the relationship between the level of microplastics (considered a pollutant) in fresh water and stress response in freshwater mussels (with a higher level of stress indicating shorter survival times).
(a) Go to the course webpage and under Datasets, download the CSV file “exposure.csv” and follow the accompanying Minitab instructions. Copy and paste the Fitted Line Plots and the Residual Plots in a blank document. Print these out and attach them to your homework.
(b) What is the fitted equation before taking observation #21 out? What is the fitted equation after taking observation #21 out?
(c) What is the R2 for the data set before observation #21 was taken out? What is the R2 after this observation was taken out? Comment briefly on what this means.
(d) Comment on the residual plots and the Fitted Line plot for the regression model with observation #21 included and the residual plots and the Fitted Line plot for the regression model with obs. #21 taken out. What has changed after removing this point?
exposure.csv
MicroPlastic,Stress
0.1,0.07
0.45401,4.1673
1.09765,6.5703
1.27936,13.815
2.20611,11.4501
3.50064,12.9554
4.0403,20.1575
5.23583,17.5633
6.45308,26.0317
7.1699,22.7573
8.28474,26.303
9.59238,30.6885
10.92091,33.9402
11.66066,30.9228
12.79953,34.11
13.97943,44.4536
14.41536,46.5022
15.71607,50.0568
16.70156,46.5475
17.16463,45.7762
18.8234,2.3253
In: Statistics and Probability
A golf club manufacturer claims that golfers can lower their scores by using the manufacturer's newly designed golf clubs. Eight golfers are randomly selected and each is asked to give his or her most recent score. After using the new clubs for one month, the golfers are asked again to give their most recent score. The scores for each golfer are given in the table below. Is there enough evidence to support the manufacturer's claim? Let d=(golf score after using the newly designed golf clubs)−(golf score before using the newly designed golf clubs) . Use a significance level of α=0.05 for the test. Assume that the scores are normally distributed for the population of golfers both before and after using the newly designed clubs.
Golfer 1 2 3 4 5 6 7 8
Score (old design) 93 86 84 96 89 81 92 94
Score (new design) 91 90 80 92 91 77 89 87
Step 1 of 5: State the null and alternative hypotheses for the test.
Step 2 of 5: Find the value of the standard deviation of the paired differences. Round your answer to one decimal place.
Step 3 of 5: Compute the value of the test statistic. Round your answer to three decimal places.
Step 4 of 5: Find the p-value for the hypothesis test. Round your answer to four decimal places.
Step 5 of 5: Draw a conclusion for the hypothesis test.
In: Statistics and Probability
An SAT prep course claims to improve the test score of students. The table below shows the scores for seven students the first two times they took the verbal SAT. Before taking the SAT for the second time, each student took a course to try to improve his or her verbal SAT scores. Do these results support the claim that the SAT prep course improves the students' verbal SAT scores?
Let d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course)d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course). Use a significance level of α=0.01 for the test. Assume that the verbal SAT scores are normally distributed for the population of students both before and after taking the SAT prep course.
| Student | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Score on first SAT | 560 | 490 | 400 | 350 | 360 | 470 | 560 |
| Score on second SAT | 590 | 540 | 470 | 460 | 380 | 510 | 620 |
a) State the null and alternative hypotheses for the test.
b) Find the value of the standard deviation of the paired differences. Round your answer to three decimal place.
c) Compute the value of the test statistic. Round your answer to three decimal places.
d) Determine the decision rule for rejecting the null hypothesis. Round the numerical portion of your answer to three decimal places.
e) Make the decision for the hypothesis test.
In: Statistics and Probability
What Statistical Test Should I Use Please indicate the type of test needed to analyze the data described. Hints: Think about the IV and DV. How many levels of the IV? Are they repeated measures? Are the data categorical?
a. z-test
b. One-Sample t-Test
c. Dependent Measures t-test
d. Independent Measures t-test
e. One-way ANOVA
f. Post-hoc tests
g. Between-Subjects Factorial ANOVA
h. Chi-Square test of Independence
_________ A researcher is interested in finding out if the color of the classroom affects performance on a memory test. He randomly assigns 10 students to a classroom with green walls, 10 students to a classroom with purple walls, and 10 students to a classroom that has neutral colored walls (typical classroom). After the students are all assigned to their rooms they are given the memory test and scores are determined.
_________ A new drug is being tested to determine its effectiveness for decreasing depression. A group of participants are measured on depression levels before and after receiving the drug. Scores before and after were compared.
_________ Dr. Williamson wants to determine if the GPA of students in her experimental psychology class is significantly higher than the average GPA of all college students attending KSU in the same semester. The mean of all college students enrolled at KSU in the fall semester of 2008 is 2.9 and the SD is .3
. _________ Faculty teaching Experimental Psychology want to know if the statistics ability of KSU graduates differ from the national average. They know that the average on the national statistics exam is 5.8
In: Statistics and Probability
Country X and country Y both produce bicycles and sweaters. In country X each worker in a day can produce either 5 bicycles or 20 sweaters. In country Y each worker in a day can produce either 3 bicycles of 18 sweaters. Each country has constant opportunity cost of production and each has 100 workers. Enter whole numbers in each blank.
In country X the opportunity cost of producing one bicycle is ____ sweaters and in country Y the opportunity cost of producing one bicycle is_____ sweaters.
Initially the two countries do not trade. Country X allocates 60 workers to bicycle production and 40 workers to sweater production so they produce a total of ____ bicycles and _____ sweaters. Country Y allocates 60 workers to bicycle production and 40 workers to sweater production so they produce a total of ____ bicycles and ____sweaters.
The two countries decide to completely specialize and then engage in trade. With specialization country X will produce _____ bicycles and_____ sweaters, and country Y will produce ____ bicycles and ____ sweaters. The two countries decide to trade 190 bicycles in exchange for 950 sweaters. After trade country X will consume _____ bicycles and ______ sweaters, and country Y will consume_____ bicycles and ____ sweaters.
After specialization and exchange, country X is able to consume____ more bicycles and _____ more sweaters than it could before trade. Country Y is able to consume ____ more bicycles and_____ more sweaters after specialization and exchange than it could before specialization and exchange.
In: Economics
An SAT prep course claims to improve the test score of students. The table below shows the scores for seven students the first two times they took the verbal SAT. Before taking the SAT for the second time, each student took a course to try to improve his or her verbal SAT scores. Do these results support the claim that the SAT prep course improves the students' verbal SAT scores?
Let d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course)d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course). Use a significance level of α=0.01 for the test. Assume that the verbal SAT scores are normally distributed for the population of students both before and after taking the SAT prep course.
| Student | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Score on first SAT | 470 | 470 | 510 | 410 | 400 | 390 | 530 |
| Score on second SAT | 500 | 490 | 580 | 490 | 420 | 430 | 590 |
1. State the null and alternative hypotheses for the test.
2. Find the value of the standard deviation of the paired differences. Round your answer to one decimal place.
3. Compute the value of the test statistic. Round your answer to three decimal places.
4. Determine the decision rule for rejecting the null hypothesis. Round the numerical portion of your answer to three decimal places.
5. Make the decision for the hypothesis test.
In: Statistics and Probability
An SAT prep course claims to improve the test score of students. The table below shows the scores for seven students the first two times they took the verbal SAT. Before taking the SAT for the second time, each student took a course to try to improve his or her verbal SAT scores. Do these results support the claim that the SAT prep course improves the students' verbal SAT scores?
Let d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course)d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course). Use a significance level of α=0.1 for the test. Assume that the verbal SAT scores are normally distributed for the population of students both before and after taking the SAT prep course.
| Student | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Score on first SAT | 500 | 380 | 560 | 430 | 450 | 360 | 560 |
| Score on second SAT | 540 | 470 | 580 | 450 | 480 | 400 | 600 |
1. State the null and alternative hypotheses for the test.
2. Find the value of the standard deviation of the paired differences. Round your answer to one decimal place.
3. Compute the value of the test statistic. Round your answer to three decimal places.
4. Determine the decision rule for rejecting the null hypothesis. Round the numerical portion of your answer to three decimal places.
5. Make the decision for the hypothesis test.
In: Statistics and Probability
Cornerstone Exercise 16.4 (Algorithmic)
After-Tax Profit Targets
Olivian Company wants to earn $600,000 in net (after-tax) income next year. Its product is priced at $400 per unit. Product costs include:
| Direct materials | $120.00 |
| Direct labor | $88.00 |
| Variable overhead | $20.00 |
| Total fixed factory overhead | $405,000 |
Variable selling expense is $16 per unit; fixed selling and administrative expense totals $255,000. Olivian has a tax rate of 40 percent
Required:
1. Calculate the before-tax profit needed to
achieve an after-tax target of $600,000.
$
2. Calculate the number of units that will
yield operating income calculated in Requirement 1 above. If
required, round your answer to the nearest whole unit.
units
|
3. Prepare an income statement for Olivian Company for the coming year based on the number of units computed in Requirement 2. Do NOT round interim calculations and, if required, round your answer to the nearest dollar.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||
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4. What if Olivian
had a 35 percent tax rate? Would the units sold to reach a $600,000
target net income be higher or lower than the units calculated in
Requirement 2?
- Select your answer -HigherLowerCorrect 1 of Item 3
Calculate the number of units needed at the new tax rate. In
your calculations, round before-tax income to the nearest dollar.
Round your answer to the nearest whole unit.
units
In: Accounting
An SAT prep course claims to improve the test score of students. The table below shows the scores for seven students the first two times they took the verbal SAT. Before taking the SAT for the second time, each student took a course to try to improve his or her verbal SAT scores. Do these results support the claim that the SAT prep course improves the students' verbal SAT scores?
Let d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course)d=(verbal SAT scores prior to taking the prep course)−(verbal SAT scores after taking the prep course). Use a significance level of α=0.05α=0.05 for the test. Assume that the verbal SAT scores are normally distributed for the population of students both before and after taking the SAT prep course.
| Student | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Score on first SAT | 570 | 410 | 450 | 440 | 550 | 420 | 370 |
| Score on second SAT | 600 | 500 | 510 | 520 | 570 | 450 | 430 |
1) State the null and alternative hypotheses for the test.
2) Find the value of the standard deviation of the paired differences. Round your answer to three decimal place.
3) Compute the value of the test statistic. Round your answer to three decimal places.
4) Determine the decision rule for rejecting the null hypothesis. Round the numerical portion of your answer to three decimal places.
5) Make the decision for the hypothesis test.
In: Statistics and Probability