A true/false test has 30 questions. A passing grade is 78% or more correct answers.
a. What is the probability that a person will guess correctly on one true/false question?
b. What is the probability that a person will guess incorrectly on one question?
c. Find the approximate probability that a person who is just guessing will pass the test.
d. If a similar test were given with multiple-choice questions with four choices for each question, would the approximate probability of passing the test by guessing be higher or lower than the approximate probability of passing the true/false test? Why?
In: Statistics and Probability
A true/false test has 100 questions. A passing grade is 64% or more correct answers. a. What is the probability that a person will guess correctly on one true/false question? b. What is the probability that a person will guess incorrectly on one question? c. Find the approximate probability that a person who is just guessing will pass the test. d. If a similar test were given with multipl-choice questions with four choices for each question, would the approximate probability of passing the test by guessing be higher or lower than the approximate probability of passing the true/false test? Why?
In: Statistics and Probability
It’s the year 1995 and John Smith is staying overnight at a
hotel before an important meeting the next morning. He asked the
customer service desk to give him a 7 am wake-up call. The
probability that he gets the call is 0.9. If he gets the call, the
probability that he will arrive for the meeting on time is 0.9. If
the call is not given, the probability that he will be on time for
the meeting is 0.4.
a) Calculate the probability that John Smith will not arrive on
time for the meeting.
b) If John Smith is on time for the meeting, what is the
probability that the wake-up call was not made?
In: Statistics and Probability
A certain weightlifter is prone to back injury. He finds that he has a 20% chance of hurting his back if he uses the proper form of bending at the hips and keeping his spine locked. The probability that he will hurt his back with bad form is 95%. The probability that he uses proper form is 75%.
A. What is the probability that he hurts his back and has proper form?
B. What is the probability that he doesn't hurt his back and has proper form?
C. What is the probability he doesn't hurt his back?
In: Statistics and Probability
Bad gums may mean a bad heart. Researchers discovered that 78% of people who have suffered a heart attack had periodontal disease, an inflammation of the gums. Only 29% of healthy people have this disease. Suppose that in a certain community heart attacks are quite rare, occurring with only 14% probability.
A. If someone has periodontal disease, what is the probability that he or she will have a heart attack?
Probability =
B. If 44% of the people in a community will have a heart attack, what is the probability that a person with periodontal disease will have a heart attack?
Probability =
In: Math
Suppose that 1/2 of all cars sold at a Nissan dealer in a given year are Altimas, 1/3 are Maximas, and the rest are Sentras. Suppose that 3/4 of the Altimas, 1/2 of the Maximas, and 1/2 of the Sentras have a moon roof. Answer the following questions. For each question, first decide whether the probability is a conditional probability or not.
What is the probability a randomly selected car has a moon roof?
What is the probability that a randomly selected car has a moon roof given it is a Sentra?
What is the probability a randomly selected car is a Maxima if it has a moon roof?
In: Math
Is the law of large numbers a phenomenon? If something is random, then how can we define an average outcome?
In: Statistics and Probability
What percentage of the first 500 natural number can be written as the difference of two perfect square?
In: Computer Science
What is the quickest way to determine if a number is a perfect square?
In: Advanced Math
What is the least natural number that should be added to 7832 to make it a perfect square?
In: Math