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