Author Question: Suppose that a quiz consists of 20 True-False questions. A student hasn't studied for the exam and ... (Read 155 times)

bobbie · **on:** Jul 24, 2018

Suppose that a quiz consists of 20 True-False questions. A student hasn't studied for the exam and will just randomly guesses at all answers (with True and False equally likely). How would you find the probability that the will student get 8 or fewer answers correct?
a. Find the probability that X = 8 in a binomial distribution with n = 20 and p = 0.5.
b. Find the area between 0 and 8 in a uniform distribution that goes from 0 to 20.
c. Find the probability that X = 8 for a normal distribution with mean of 10 and standard deviation of .
d. Find the cumulative probability for 8 in a binomial distribution with n = 20 and p = 0.5.

Question 2

Conscientiousness is a tendency to show self-discipline, act dutifully, and aim for achievement. The trait shows a preference for planned rather than spontaneous behavior. A random sample of 650 students is asked to fill out the Hogan Personality Inventory (HPI) to measure their level of conscientiousness. The 300 undergraduate students scored an average of 145 with a standard deviation of 16 . The 350 graduate students had a mean score of 153 with a standard deviation of 21 . What is the standard error for the difference between the two sample means?
a. 18.5
b. 2.11
c. 1.45
d. 2.05