Stats Chapter 3 to 6 MidTerm Study Guide
Suppose that 14% of all students on campus wear glasses. If two students are chosen at random, what is the probability that both of them wear glasses? Is the outcome of wearing or not wearing glasses of both students independent or dependent?
0.14 x 0.14 = 0.0196 Independent
In a large population, 52 % of the people have been vaccinated. If 5 people are randomly selected, what is the probability that AT LEAST ONE of them has been vaccinated?
0.9745
If the coin is not fair, but with 45% chance of getting ahead, what can P(X) be modeled by?
Binomial distribution with n=40, p=0.45
If X is the number of heads obtained in 40 independent tosses of a fair coin, then X can be modeled by:
Binomial distribution with n=40, p=0.5
The age of a college professor chosen at random.
Continuous
The amount of water you drink on a random day.
Continuous
Which of the following statements is correct about a density function f(x)?
Correct statements: Total area under the density function is 1, f(a) must be positive, area under the density function gives probability of X in a range.
What is a dependent event?
Dependent events influence the probability of other events - or their probability of occurring is affected by other events.
The number of ships in Pearl Harbor on any given day.
Discrete
The number of times you say the word "please" during a random conversation.
Discrete
The number that comes up on the roll of a die.
Discrete
Which of the following statements is correct about Standard Normal Distribution?
Mean = 0 and SD = 1
What is an independent event?
Independent events do not affect one another and do not increase or decrease the probability of another event happening.
About 24% of flights departing from New York's John F. Kennedy International Airport were delayed in 2009. Assuming that the chance of a flight being delayed has stayed constant at 24%, we are interested in finding the probability of 10 out of the next 100 departing flights being delayed. Noting that if one flight is delayed, the next flight is more likely to be delayed, which of the following statements is correct?
We cannot calculate this probability using the binomial distribution since whether or not one flight is delayed is not independent of another.
Which of the following statements are correct about z in a standard Normal distribution?
Z is the number of SD from the mean for a normally distributed random variable, Z is significantly large if z is greater than 2.
Which of the following statements are correct about distribution of Standard Normal? Select all that apply)
It models z-score of a normally distributed random variable, standard normal has a symmetric bell shape distribution.
Which of the following statements is false?
Two independent events cannot occur at the same time.