Ch13-15_Group_QUIZ.pptx - CH13-15 GROUP QUIZ 1 Two friends...

CH13-15 GROUP QUIZ

1) Two friends, Ty and Skya, take a quiz every
week. From past experiences, it is known that
both friends’ scores are approximately normally
distributed, where Ty has a mean score of 90
with a standard deviation of 12, and Skya has a
mean score of 85 with a standard deviation of 6.
Assuming that their scores are independent,
which of the following values is closest to the
probability that Ty will have a lower score than
Skya in a single quiz?
A) 0.35
B) 0.39
C) 0.32
D) 0.20
E) None of these
A

A survey asks a random sample of 100 OHS students if
they support an increase in game tickets with additional
revenue covering expense of academic tutors for
students involved in extra-curricular activities. Let X
denote the number in the sample that say they support
the increase. Suppose 40% of all students at OHS
support the increase.
2. The expected value (mean) of X is:

3) Mr. and Mrs. Garcia have each decided to
provide extra credit points each week for the next
6 weeks. Suppose the amount of extra credit
points provided in a week by Mr. Garcia is
normally distributed with a mean of 5 points and
a standard deviation of 1 point, and the amount of
extra credit points provided in a week by Mrs.
Garcia is normally distributed with a mean of 6
points and a standard deviation of 2 points. What
is the expected number of weeks in a 6 week
period that their combined extra credit will
exceed 10 points?
2

4. The standard deviation of X is: