Stats Study for Test 3

Which of the following is NOT needed to determine the minimum sample size required to estimate a population proportion

Standard Deviation

90% confidence level, whats the critical value

1.645

95% confidence level, whats the critical value

1.96

Which of the following is NOT an equivalent expression for the confidence interval given by 161.7<mean<189.5

161.7(+-) 27.8

99% confidence level, whats the critical value

2.576

About​ ______% of the area is between z=−1 and z=1 ​(or within 1 standard deviation of the​ mean).

68.27

About​ ______% of the area is between z=−2 and z=2 ​(or within 2 standard deviations of the​ mean).

95.45

About​ ______% of the area is between z=−3 and z=3 ​(or within 3 standard deviations of the​ mean).

99.73

About​ ______% of the area is between z=−3.5 and z=3.5 ​(or within 3.5 standard deviations of the​ mean).

99.95

Which of the following is NOT an observation about critical values

A critical value is the area in the right-tail region of the standard normal curve

Which of the following is not a commonly used​ practice?

If the distribution of the sample means is normally​ distributed, and n>​30, then the population distribution is normally distributed.

A researcher collects a simple random sample of​ grade-point averages of statistics​ students, and she calculates the mean of this sample. Under what conditions can that sample mean be treated as a value from a population having a normal​ distribution?

If the population of grade-point averages has a normal distribution and the sample has more than 30 grade-point averages

The ____ states that if, under a given assumption, the probability of a particular observed event is exceptionally small​ (such as less than​ 0.05), we conclude that the assumption is probably not correct.

Rare event Rule for Inferential statistics

Which of the following is NOT a conclusion of the Central Limit​ Theorem?

The distribution of the sample data will approach a normal distribution as the sample size increases.

What does the notation zα ​indicate?

The expression zα denotes the z score with an area of α to its right.

Which of the following is NOT a descriptor of a normal distribution of a random​ variable?

The graph is centered around 0.

Which of the following is NOT true of the confidence level of a confidence interval

The is a 1-a chance, where a is the complement of the confidence level, that the true value of p will fall in the confidence interval produced from out sample

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 standard deviation=1

Which of the following calculations is NOT derived from the confidence interval

The population mean

What is the difference between a standard normal distribution and a nonstandard normal​ distribution?

The standard normal distribution has a mean of 0 and a standard deviation of​ 1, while a nonstandard normal distribution has a different value for one or both of those parameters.

Which concept below is NOT a main idea of estimating a population proportion

Using a sample statistic to estimate the population is utilizing descriptive statistics

Which of the following would be a correct interpretation of a 99% confidence interval such as 4.1<mean<5.6?

We are 99% confident that the interval from 4.1 to 5.6 actually does contain the true value of mean.

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

The ___ tells us that for a population with any distribution, the distribution of the sample means approaches a normal distribution as the sample size increases

central limit theorem

The​ _______ tells us that for a population with any​ distribution, the distribution of the sample means approaches a normal distribution as the sample size increases.

central limit theorem

The number of ___ for a collection of sample data is the number of sample values that can vary after certain restrictions have been imposed on all data values

degrees of freedom

Which of the following groups has terms that can be used interchangeably with the others?

percentage, probability and proportion

A __is a single value used to approximate a population parameter

point estimate

The ___ is the best point estimate of the population mean

sample mean

The standard deviation of the distribution of the sample mean is ____

standard deviation divided by square root of N

Which of the following is NOT a requirement for constructing a confidence interval for estimating a population mean with standard deviation known?

the confidence level is 95%

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

Which of the following is NOT required to determine minimum sample size to estimate a population mean?

the size of the population, N

A critical value, Z, denotes the _____

z-score with an area of a to its right

Weights of golden retriever dogs are normally distributed. Samples of weights of golden retriever​ dogs, each of size n=​15, are randomly collected and the sample means are found. Is it correct to conclude that the sample means cannot be treated as being from a normal distribution because the sample size is too​ small? Explain.

​No; the original population is normally​ distributed, so the sample means will be normally distributed for any sample size.