exam 2 HW questions Flashcards
The standard normal distribution
Has a mean if 0 and a standard deviation of 1
True or False: The probability that a standard normal variable, Z, is between 1.50 and 2.10 is the same as the probability Z is between – 2.10 and – 1.50.
True
True or False: The probability that a standard normal variable, Z, is less than 5.0 is approximately 0.
False
what is another name for the mean of a probability distribution
expected value
In a a poisson distribution what is the same
Mean and variance
What is a event of interest called in a binomial distribution
Success
Suppose you were given the average number of medical errors at a hospital and you wished to compute the probability of 10 or fewer errors in the upcoming year. You would use the discrete probability distribution known as a ___________ distribution. {Fill in the blank with one word.}
Poisson probability
Suppose the company you work for bids on 500 contracts a year. The probability of winning a bid is the same for each contract (0.10) and contract wins are independent events. If the company would ilke to know the probability of winning 60 or more contracts, it would use the discrete probability distribution known as a ___________ distribution. {Fill in the blank with one word.}
Binomial probsbility
The Central Limit Theorem is important in statistics because
for a large n, it says the sampling distribution of the mean is approximately normal, regardless of the shape of the population.
The standard error of the mean for a sample of 100 (n=100) is known to be 30. To reduce the standard error of the mean to 15, we would
increase the sample size to 400.
The standard error of the proportion will become larger
as the population proportion gets closer to 0.50
The sample proportion is an unbiased estimate of the population proportion.
true
The sample mean is an unbiased estimate of the population mean.
True
if n=12 and pi = 0.45, we can approximate the binomial distribution with the normal distribution.
True
