MATH WK5 Binomial Distribution Quiz,
workbook, & exam
If five students take Exam 1 and score 81, 85, 89, 93, and 97, what is the variance on Exam 1? - correct
answer Determine that the average score is 89
Determine that the differences between each score and the mean are -8, -4, 0, 4, 8
Square all of the differences to get 64, 16, 0, 16, 64
Take the average of the squared differences to get 32
Answer: 32
If five students take Exam 2 and score 83, 83, 84, 94, 96, what is the standard deviation of Exam 2?
(Round your answer to the nearest whole number.) - correct answer Calculate the
variance of Exam 2 by going through each of the four steps:
Determine that the average score is 88
Determine that the differences between each score and the mean are -5, -5, -4, 6, 8
Square all of the differences to get 25, 25, 16, 36, 64
Take the average of the squared differences to get 33.2
The standard deviation on Exam 2 is equal to the square root of the variance
Take the square root of the variance to get 5.76
Round to the nearest whole number to get 6
Answer: 6
If instead of scoring 83 on Exam 2 (83, 83, 84, 94, 96), one of the students scored 85, how will that affect
the mean and standard deviation of Exam 2? - correct answer The mean will
increase, but the standard deviation will decrease.
If five students take Exam 1 and score in the range of 81 to 97 and 5 student take Exam 2 and score in
the range of 83 to 95, which test has more variance? - correct answer There is not
enough info to tell
, If five students take Exam 1 and score 81, 85, 89, 93, and 97 and five students take Exam 2 and score 83,
89, 91, 92, 95, which test has more variance?
If five students take Exam 1 and score 81, 85, 89, 93, and 97 and five students take Exam 2 and score 83,
83, 84, 95, 96, which test has more variance? - correct answer - Exam 1
- Exam 2
If Apple and Microsoft tend to move in the same direction, what type of covariance do they exhibit?
If the stock prices of Ford Motors and General Motors both fell during the recession, what type of
covariance did they exhibit? - correct answer - Positive Covariance
- Positive covariance
The weather in Seattle has no impact on the weather in Los Angeles. What type of covariance do Seattle
and Los Angeles exhibit?
When people are watching Netfix, HBO viewership goes down. What type of covariance is there
between Netfix and HBO viewership? - correct answer - No Covariance
- Negative Covariance
As gas prices increase, people avoid using their car and are more likely to carpool, which reduces their
driver miles. Gas prices and driver-miles exhibit what type of covariance?
Every 365 days the earth orbits the sun, producing four seasons. Every 27 days, the moon orbits the
earth, producing different phases. What is the covariance between the phase of the moon and the
season? - correct answer - Negative covariance (Since gas prices and driver miles
move together, but in opposite directions, they exhibit negative covariance)
