Determine the variables tested in the experiment. (multiple choice)?
If applicable, determine and identify any positive or negative controls. A study is being done to test the effects of habitat space on the size of fish populations. Different sized aquariums are set up with six goldfish in each one. Over a period of six months, the fish are fed the same type and amount of food. The aquariums are equally maintained and cleaned throughout the experiment. The temperature of the water is kept constant. At the end of the experiment the number of surviving fish is surveyed. A. Independent Variable: B. Dependent Variable: C. Controlled Variables/Constants: D. Experimental Controls/Control Groups:
What is the dependent variable in the experiment? (multiple choice)?
A. The age of the rats B. The amount of drug given to the rats C. The saline solution given to the rats D. The weight of the rats Your lab is studying an experimental drug that may be able to prevent obesity. You are testing the drug on rats for a preliminary analysis. You have chosen four groups of rats from the laboratory rat–rearing facility, ensuring that they have the same age, history, and other characteristics. You give three experimental groups the drug, dissolved in saline solution and administered via injection. The first group receives a low dose, and the second, a moderate dose and the third a high dose. You give the fourth group an injection of fluid without the drug. You feed these groups three times a day with an adjusted diet equivalent to a human being's intake of excessive calories, designed to simulate obesity-inducing food quantities. You measure the rats' weights and average the weights per group. You conduct these measurements on a daily basis for thirty days in the early morning before the feedings. The following are the groups and the treatments you give them: Group A -obesity diet, low drug dose Group B – obesity diet, moderate drug dose Group C -obesity diet, high drug dose Group D - obesity diet, fluid without drug
What will be the answer if a multiple choice test consisting of 10 questions with four choices each, and the student guesses the answer to each question? What is the probability that he gets 8 questions correctly?
For each question we have 4 choices. So if you have 10 on such questions, you ll have :4*4*4*4*4*4*4*4*4*4= 4^10 = 2048Getting 8 correct means=> 8 corrects and two wrongs3/4 is the probability if a question is answered wrong1/4 is the probability if a question is answered correctlyso we can consider this probability :P=(3/4)*(3/4)*(1/4)*(1/4)*(1/4)*(1/4)*(1/4)*(1/4)*(1/4)*(1/4)=> P=0.00000858306But as we can select any combination of 2 from 10 for being wrong, so we need to multiply P by (10,2)=10!/(2!*8!) =45so the answer is P*45 = 0.00038623809So not very lucky to answer randomly!By the way, is it a question from your home work assignment? ;) ;)
On a multiple choice examination with 3 possible answers for each of the 5 questions, what is the probability that a student would get 4 or more correct answers just by guessing?
So each question has 3 options: 2 incorrect and 1 correct.Probability of a random guess being correct = 1/3So probability (4 or more correct) = probability (4 correct & 1 incorrect) + probability (5 correct).Since each answer to those 5 questions can be either correct or incorrect with probability of correct ( say p) = 1/3 and incorrect (say q) = 1-p= 2/3, follows a binomial distribution, with total cases n=5So required probability= (4 correct & 1 incorrect) or (all 5 correct)=( 5C4*((1/3)^4)*(2/3)) + (5C5*((1/3)^5)*(2/3)^0)= 5*2/3^5 + 1/3^5= 11/243
A multiple-choice quiz has 15 questions, each with 4 possible answers of which only 1 is the correct answer?
IF the student has not studied, so the questions are answered by choosing randomly (as close to randomly as a person can do), then the number of correctly answered questions could be considered binomial*, with n = 15 and p = 0.25. That distribution can be used to find the probability. The troubling part would be assuming the answers to different questions are selected independently, required for the binomial. If the test-taker makes each decision in his/her head, this independence assumption is probably not met, and the binomial answer would apply only approximately. A method bringing the choices closer to mutual independence would be to have a "spinner" like board games used to use, with the circle divided into quarters of equal size, one named "A", one named "B", one named "C", and the last named "D". For each question spin the spinner, and select the answer that corresponds to the sector of the circle. Neither perfectly random nor completely independent, but closer than you get by making choices by personal choice. Of course, if the student studies, then there is no easy answer to this at all.
A multiple choice quiz has 15 questions with 4 choices, of which 1 answer is correct. What is the probability of getting 11 answers correct?
There are 15 questions in total question. Each question has 4 options out of which one is correct.So the probability of getting a correct answer in each case is [math]\frac{1}{4}[/math] and that of incorrect answer is [math]\frac{3}{4}[/math] . So, this can be looked upon as Bin(15,[math]\frac{1}{4}[/math]) distribution. So, the required probability is,[math]15C11×({\frac{1}{4}})^{11}×({\frac{3}{4}})^4[/math]=[math]1.0297×10^{-4}[/math]If you do not understand this, read the following method.Each question can be answered in 4 ways.The total number of ways in which 15 questions can be answered=[math]4^{15}[/math]Out of this we will calculate the number of favourable selections. Firstly,we need 11 correct answers. We can select 11 out of 15 questions in [math]15C11 [/math]ways. For each of the selected 11 questions, the correct answer can be selected in just 1 way. For each of the remaining 4 questions, we can select incorrect answer in 3 ways. So, the number of favourable selections=[math]15C11×1^{11}×3^4=110565.[/math]Going the classical definition of probability, the required probability=[math]\frac{110565}{4^{15}}=1.0297×10^{-4}[/math]Note: If you look carefully at the calculation, both methods are exactly same :p
4 Biology Questions (Multiple Choice)?
1. D - artificial selection would weed out the cows that produce less milk, and the more productive cows would (in theory) go on to produce more milk, and breed to make more productive cows. 2. B - in order to test the effect of a change, you can't have interfering changes. Ex, if both variables X and Y are changing, what is causing effect Z? 3. A - preserved remains of ancient organisms: fossils. 4. A - a good example of an acquired characteristic is muscles. A buff man doesn't necessarily go on to produce buff kids, right? The nature of the acquired characteristic is that it doesn't change the organism's DNA.
Statistics Multiple Choice questions?
Two weeks prior to final exams, 10 undergraduate students took part in an experiment to determine what effect the presence of a live plant, a photo of a plant, or absence of a plant has on the student’s ability to relax while isolated in a dimly lit room. Each student participated in three sessions: one with a live plant, one with a plant photo, and one with no plant (control). During each session, finger temperature was measured at one-minute intervals for 20 minutes. Since increasing finger temperature indicates an increased level of relaxation, the maximum temperature was used as the response variable. Note: Some assumptions of parametric test were violated. 1. What non-parametric test would you suggest to the researchers to use? a. Friedman test b. Mann-Whitney test c. Kruskal-Wallis test d. Wilcoxon rank-sum test Question 2 What is the researchers’ hypothesis? a. Finger temperature differs between students b. Finger temperature does not differ between students c. Students’ finger temperature does not depend on the experimental conditions d. Students’ finger temperature depends on the experimental conditions Question 3 The observed test-statistic is 0.20. What is its reference distribution? a. F(2, 18) b. z c. t(18) d. Chi-square(2) Question 4 The observed test-statistic is 0.20, with p-value = 0.9048. What can the researchers conclude? Answer a. Students’ finger temperature does not depend on the experimental conditions b. There is no evidence that students’ finger temperature depends on the experimental conditions c. Finger temperature does not differ between students d. There is no evidence that finger temperature differs between students Question 5 The observed test-statistic is 0.20, with p-value = 0.9048. Which is correct? a. To conduct a non-parametric post hoc test, we use the Tukey method b. To conduct a non-parametric post hoc test, rather than using 0.05 as our critical level of significance, we need to adjust the alpha level by the number of comparisons we are conducting. c. There is no need to do any post hoc tests for this study d. To conduct a non-parametric post hoc test, we use Bonferroni correction
Can anyone help me understand how to find sample test statistics and P-Values?
The U.S. Department of Transportation, National Highway Traffic Safety Administration, reported that 77% of all fatally injured automobile drivers were intoxicated. A random sample of 53 records of automobile driver fatalities in a certain county showed that 34 involved an intoxicated driver. Do these data indicate that the population proportion of driver fatalities related to alcohol is less than 77% in Kit Carson County? Use α = 0.10. What is the value of the sample test statistic? (Round your answer to two decimal places.) Find the P-value of the test statistic. (Round your answer to four decimal places.) Thank you in advanced, I promise award the ten points to the best explanation!!
How do teachers come up with wrong answer choices on tests and quizzes?
When I’m doing multiple choice (which is rare), here’s my algorithm:Write the question.Find the correct answer. Make it “A”.Think about the most common way students are likely to screw up that question.Find the answer that you get when you make that mistake. Make it “B”.Think about a less common way students are likely to screw up that question.Find the answer that you get when you make that mistake. Make it “C”.Pick two numbers from the question. Multiply them together. Make it “D”.Shuffle your answers randomly.Repeat steps 1 - 8 until you have a suitable number of questions.I tell my students this, by the way. I walk them through the process of writing tests. I do this for two reasons:I want my students to know that if they make all the common goofs, they’ll find the “sexy wrong answers” they’re looking for. They look so right…but they’re so wrong. ;) This way, they hopefully study the common mistakes so they don’t make them.Standardized tests are written more or less in this fashion. More advanced techniques are used, to be sure, but the basic premise is the same: Right, Sexy Wrong, Somewhat reasonable, Obviously flawed. If they get used to it in my class, they’ll be more likely to spot the wrong answers on the ACT/SAT.It has been my experience, both personally and through my students, that the smartest students don’t always get the highest test scores. Neither do the hardest working students. The students who get the highest test scores are the ones that are very good (but not necessarily the best) at the subject, and very hard working (but not necessarily the hardest working), and the ones who understand tests and how to dissect them.Taking tests is a skill, just like shooting free throws or playing the violin. Practicing, analyzing your practice, modifying your practice, and then repeating over and over again is the ticket if you want to be a test ninja.