Chapter 6 STP 226 Vocab
Which statistics are unbiased estimators of population parameters?
- Sample variance used to estimate a population variance. - Sample mean used to estimate a population mean. - Sample proportion used to estimate a population proportion.
Which of the following are descriptors of a normal distribution of a random variable?
- The graph is centered around the mean - The graph of the distribution is bell-shaped - The graph of the distribution is symmetric
Which of the following describe the standard normal distribution?
- The graph is symmetric. - The total area under the curve must equal 1. - It is a normal distribution with a mean of 0 and a standard deviation of 1.
Which of the following groups of terms can be used interchangeably when working with normal distributions?
- areas - probability - relative frequencies
If you are asked to find the 85th percentile, you are being asked to find _____.
a data value associated with an area of 0.85 to its left
What conditions would produce a negative z-score?
a z-score corresponding to an area located entirely in the left side of the curve
Finding probabilities associated with distributions that are standard normal distributions is equivalent to _______.
finding the area of the shaded region representing that probability
The _____ _____, denoted by p hat, is given by the formula p hat = _____ , where x is the number of individuals with a specified characteristic in a sample of n individuals.
sample proportion, x/n
The notation P(z<a) denotes _______.
the probability that the z-score is less than a
Where would a value separating the top 15% from the other values on the graph of a normal distribution be found?
the right side of the horizontal scale of the graph
A data value is considered _______ if its z-score is less than minus −2 or greater than 2.
unusual
When a data value is converted to a standardized scale representing the number of standard deviations the data value lies from the mean, we call the new value a _______.
z-score
Which of the following is a biased estimator? That is, which of the following does not target the population parameter?
Median
What requirements are necessary for a normal probability distribution to be a standard normal probability distribution?
The mean and standard deviation have the values of μ=0 and σ=1.
_____________ is the distribution of all values of the statistic when all possible samples of the same size n are taken from the same population.
The sampling distribution of a statistic
_____________ is the distribution of sample proportions, with all samples having the same sample size n taken from the same population.
The sampling distribution of the proportion
True or False: The mean of the sampling distribution of p hat is p.
True
A z-score is an area under the normal curve.
Correct
True or False: The population proportion and sample proportion always have the same value.
False
