Question

In: Statistics and Probability

Several psychology students are unprepared for a surprise​ true/false test with 13 ​questions, and all of...

Several psychology students are unprepared for a surprise​ true/false test with 13 ​questions, and all of their answers are guesses.

a. Find the mean and standard deviation for the number of correct answers for such students.

b. Would it be unusual for a student to pass by guessing​ (which requires getting at least 11 correct​ answers)? Why or why​ not?

Solutions

Expert Solution

Given there is a surprise​ true/false test with 13 ​questions.

Therefore, the probability of correctly guessing the answer is p=0.5

Let "X' be the answers correcly guess by a student.

Therefore,

The pmf od X is:

for x=0,1,2,...,n

a) The mean of the binomial distribution is:

The standard deviation is:

b) The probability that the student getting at least 11 correct​ answers is given by:

Since the probability is less than 0.05, we say that it is unusual for a student to pass by guessing​.

orchestra answered 2 years ago
Next > < Previous

Related Solutions

Mary's Final for Psychology has 10 True/False questions and 10 multiple choice questions with 4 choices...
Mary's Final for Psychology has 10 True/False questions and 10 multiple choice questions with 4 choices for each answer. Assuming Mary randomly guesses on every question: a.) What's the probability that she gets at least 6 of the 10 true/false questions correct? b.) What's the probability that she gets at least 6 of the 10 multiple choice questions correct? c.) If the multiple choice questions had 5 choices for answers instead of 4, what's the probability that she gets at...
True/ False Questions: For the following questions, first write whether they are true or false then...
True/ False Questions: For the following questions, first write whether they are true or false then write in a few sentences why it’s true or false. (1.5) a. The processes for producing penicillin and blue cheese both use the Penicillium fungus.     b. The reproductive organs of Amanita muscaria are popular pizza toppings.     c. The fungus Claviceps purpurea is thought to have triggered the infamous Salem witch trials.     d. Saccharomyces cerevisiae is a common household bread mold.    ...
Psychology True and False Questions 1. Someone who develops major depression is likely to remain permanently...
Psychology True and False Questions 1. Someone who develops major depression is likely to remain permanently depressed, unless he or she gets therapy. True/ False 2. How we interpret or make meaning of a potentially stressful event can lead to negative health consequences. True/ False 3. Diagnoses of mental illness are based on both symptoms and laboratory tests. True/False 4. Community psychology and clinical psychology are basically the same thing. True/False 5. The birth of community psychology was at the...
Psychology True and False Questions 1. Someone who develops major depression is likely to remain permanently...
Psychology True and False Questions 1. Someone who develops major depression is likely to remain permanently depressed, unless he or she gets therapy. True/ False 2. People diagnosed with schizophrenia typically have two or more personalities that alternate taking control of the body. True/False 3. Panic disorder is equally common in men and women, young and old. True/False 4. Severe stress produces many of the same symptoms as illness. True/ False 5. How we interpret or make meaning of a...
C++ Questions: 1. True/False: an int uses 4 bytes in memory on all systems. 2. True/False:...
C++ Questions: 1. True/False: an int uses 4 bytes in memory on all systems. 2. True/False: a double typically offers better precision than a float. 3. True/False: The following two statements are equivalent assuming isPair is a variable of type bool: if (isPair) if (isPair == true) 4. Provide a value we could put in the blank so that the value of x will be 20 after the code snippet. int x = _____; x *= 4; 5. Provide a...
A test consists of 20 true or false questions. To get an A, you must answer...
A test consists of 20 true or false questions. To get an A, you must answer at least 18 questions correctly. If you guess on each question, what is the probability that you will get an A? Use the Standard Normal Table to find the indicated probabilities: a b c d
A true/false test has ? = 20 questions. If a student is simply guessing the answers...
A true/false test has ? = 20 questions. If a student is simply guessing the answers (so there is a 50% chance of getting correct for each question), a) what is the mean and standard deviation of the number of questions the student would get correct? Mean = ______, Standard deviation = ______ b) what is the approximate probability (approximated by a normal distribution) that this student would get at least 15 questions correct? P (at least 15 questions correct)...
Steve is about to write a test with 10 true or false questions and 15 multiple...
Steve is about to write a test with 10 true or false questions and 15 multiple choice questions. Steve has been studying hard so we’ll give a 75% chance of getting any of the 25 questions right. Assume all the questions are independent of each other. (a) (2 points) What is the probability that Steve gets exactly two thirds of the multiple choice questions right? (b) (3 points) What is the probability that Steve gets exactly half the true or...
A student takes an exam containing 13 true or false questions. At least 9 correct answers...
A student takes an exam containing 13 true or false questions. At least 9 correct answers are required to pass. If the student guesses, what is the probability that he will pass? Round your answer to four decimal places.
Answer all questions true or false Communication across all sectors of the health arena is critical...
Answer all questions true or false Communication across all sectors of the health arena is critical to quality care. Group of answer choices True False 2. Communication between provider and consumers affects every facet on the health continuum from health promotion and disease prevention to assessment, diagnosis, and treatment. Group of answer choices True False 3. Treatment adherence leads to better health out- comes and no adherence places the patient at risk for poor recovery and dis- ease progression. Group...
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT