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.
