In: Statistics and Probability
1.You attend a public health conference for student research. You count 23 posters presented by undergraduate students and 46 posters presented by graduate students. Out of all the posters, 15 posters included research on infant health concerns, 28 focused on young adult health concerns, and 14 discussed health concerns for senior citizens.
You pick a random poster to read. What is the probability you pick a poster presented by a graduate student?
What is the probability you pick a poster discussing young adult health concerns?
2.Use the standard normal distribution to calculate the following probabilities:
Cumulative area to the left:
P (z < 1.20) =
P (z < -1.09) =
P (z < 2.34) =
Cumulative area to the right:
P (z > 1.23) =
P (z > -2.05) =
P (z > 3.50) =
Subtracting cumulative areas:
P (-1.23 < z < 1.23) =
P (1.55 < z < 2.25) =
P (-3.50 < z < 2.50) =
3.An I.V. bag dispenses between 500 ml and 1000 ml of fluid, following a uniform distribution.
a. Draw the distribution below. Include the probability function (the answer to 3b).
b. What is the probability function for the amount of fluids dispensed?
c. What is the probability that the amount of fluids dispensed will be less than 750 ml?
d. What is the probability that the amount of fluid dispensed will be between 500 ml and 1000 ml?
e. What is the probability that the amount of fluid dispensed will be between 600 ml and 800 ml?
4.I recently asked 100 middle school students to complete a statistics test. The mean score on the test was 30 points with a standard deviation of 5 points. The scores followed a normal distributions. Using this information, calculate the following:
a. What is the probability a student earned a score of 45 points or less?
P (score < 45 points) =
b. What is the probability a student earned a score higher than 30 points?
P(score > 30) =
c. What is the probability a student earned a score between 25 and 45 points?
P (25 points < score < 45 points) =
d. I want to know the cutoff value for the upper 10%. What score separates the lower 90% of scores from the upper 10%?
P (score < _______) = 90% or 0.90 cumulative area to the left
e. I want to know the cutoff values for the lowest 25%.
P (score < ________) = 25% or 0.25 cumulative area to the left
f. I would also like to know the cut off values for the highest 25%.
P (score > _______) = 25% or 0.25 cumulative area to the right