Some people are concerned that new tougher standards and high-stakes tests adopted in many states have driven up the high school dropout rate. The National Center for Education Statistics reported that the high school dropout rate for the year 2004 was 10.3%. One school district whose dropout rate has always been very close to the national reports that 210 of their 1782 high school students dropped out last year. Is this evidence that their dropout rate may be increasing? Explain. The sample proportion is _____________.     Is this evidence that their dropout rate may be increasing since 2004? Conduct a hypothesis test using 5% as the significance level.   State the null and alternative hypothesis.

Q: How would you explain the analysis of variance, assuming that your audience has not had a statistics…

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Q: Based on the boxplot and descriptive statistics, which group shows more variability in narcissism…

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Q: For a severely skewed distribution, the mean often provides a better measure of central tendency…

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Q: What do you think is the reason, why researchers prefer to get a sample from the total population…

A: A researcher can carefully design the study which to a large extent try to prevent the biases and…

Q: Explain the formula for the variance of the sampling distribution of the mean?

A: Central Limit Theorem for mean: If a random sample of size n is taken from a population having mean…

Q: What does the true sampling distribution serves?

A:

Q: What is sample selection bias? Suppose you read a study using data on college graduates of the…

A: Sample selection bias: It occurs when the researcher fails to ensure the randomization in the…

Q: Does the one observed sample mean qualify as a common or a rare outcome? Explain.

A: Sample mean qualify as a common outcome if the difference between the sample mean and the actual or…

Q: Explain why you should get a much better prediction for μ by using x from a sample size n rather…

A: The confidence interval on mean is given as x-Zα2sdn≤μ≤x-Zα2sdn where  μ=population meanx=sample…

Q: the sample mean is the best estimate for population mean true or false

A: We have given that  the sample mean is the best estimate for population mean.

Q: What does the hypothesized sampling distribution serves?

A: Hypothesized sampling Distribution shows the distribution of statistics.   Generally, when conduct…

Q: Twenty years ago, 46% of parents of children in high school felt it was a serious problem that high…

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Q: Explain in your own words: What is sampling error? What is a representative random sample?

A: we explain in the following.

Q: If the sample size is n=16 what is likely true about the shape of the population?

A: Solution:  Central limit theorem: The central limit theorem state that as the sample size increases…

Q: How does a small sample size increase the effect of an outlier on the mean in a skewed distribution?…

A: A skewed distribution mean one tail is longer than the other.

Q: In your own words, give a simple explanation on why statisticians think the sample variance is…

A: We can define the bias of an estimator as the difference between this estimator's expected…

Q: what is meant by the term “sampling distribution” ?

A: A sampling distribution is a probability distribution of a statistic obtained from a larger number…

Q: 3. A Gallup poll conducted in 2010 found that 494 of 1050 adult Americans believe it is the…

A: Given that  Sample size n =1050 Favorable cases x =494 Sample proportion p^=x/n  =494/1050 =0.4705

Q: What is the population and sample of this study?

A: We want to know population and sample in given example.

Q: Why is statistical inference generally used to obtain information about a population proportion?

A: Generally, the size of the population that is considered under study is large. It would be difficult…

Q: In a sample of 81 elements, the mean was 60 and the variance was 144. What is the standard error for…

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Q: Descriptive statistics would address the problem by making generalizations or inferences about a…

A: Descriptive statistics:  Which provides the summary of data under study and it's explained already…

Q: Which statistical method would be most effective to determine if the average size of dogs in Europe…

A: Find statistical method would be most effective to determine if the average size of dogs in Europe…

Q: Would it be unusual to find a pair of samples in which the proportion of males who are left-handed…

A: Consider that n1 and n2 are defined as the sample sizes for males and females, respectively.

Q: Why doesn't it make sense to test the hypothesis that the sample mean is 42?

A: It is given that the hypothesis test is sample mean is 42.

Q: Explain about if larger the sample size, what does this reflects.

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Q: What does it mean when sample results are not statistically significant?

A: statistically significant: In principle, a statistically significant result (usually a difference)…

Q: What is the importance of getting a sample from a population? When and why is it necessary?

A: The population is defined as a large group in which the units involved have the same…

Q: What is the difference between a sample and a census? Why can it be advantageous to select a sample…

A: A census is a study of every unit, everyone or everything, in a population. It is known as a…

Q: Why is it important to report both a measure of central tendency and variability to describe a set…

A: Basic idea about measures of central tendency and dispersion Measure of Central tendency is the…

Q: For Americans using library services, the American Library Association claims that at most 70% of…

A: Here, One sample Z test is applicable. x = 85 , n = 100

Q: does this mean that the answer saying "The sample statistic equation is correct to use when the data…

A: Yes you are correct. The sample is the the subset of the population.

Q: Roughly speaking, what are the normal scores corresponding to a sample of observations?

A: The normal scores corresponding to a sample of observations are observations and expect same sample…

Q: Pick a sample problem where despite correlation, causation cannot be reasonable argument.

A: Let us take an example of sales of umbrella and sales of raincoats. Sale of raincoats Sale of…

Q: What is the relationship between the mean of a population and the mean of its sampling distribution?

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Q: Twenty years ago, 52% of parents of children in high school felt it was a serious problem that high…

A: The hypothesis tests, contain two hypothesis: null hypothesis and alternate hypothesis. The…

Q: Why does the mean inaccurately summarize a skewed distribution?

A: If the distribution is symmetric then mean is accurately summarized the data because it is exactly…

Q: the distribution of sample means consists of the

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Q: a radio talk show host asked listeners to respond either yes or no to the question,  is the…

A: Population: Population consists of the complete subjects or individuals of interest that are…

Q: How does an observed sample mean qualify as a common outcome?

A:

Q: Does having a non-significant P-value means that the means of the sample will be the same? explain

A: The hypotheses for the means is constructed as: H0: The means of the sample will be the same. H1:…

Q: The mean of a sampling distribution is smaller than the mean of the underlying population. True or…

A: We have to find that the given statement is true or false... The mean of a sampling distribution is…

Q: Too many outliers on our sample data is acceptable as long as data are summarized and presented by…

A:

Q: what happens to the mean as the sample size increases?

A: It is given that the sample size is increasing.

Q: Traditional statistics (means, variances, and hypothesis tests) are not used to evaluate the results…

A: The traditional statistics are used to evaluate the result means we use the critical values to make…

Q: A polling company contends that an agent conducts a mean of 53 in-depth home surveys every week. A…

A: Correct option is (e)

Q: If the mean time to respond to a stimulus is much higher than the median time to respond, what can…

A: There can be three different shape of the distribution: 1) Positively skewed: Most of the values…

Q: C. Under what circumstances could we consider deleting the outlier from the data and when would it…

A: Basically an outlier is an extreme observation, as shown in following figures. The point labelled…

2-Proportion Test

In a 2-proportion test, two separate proportions are measured at the same time, and their similarity is evaluated. It is also known as a 2-proportion z-test, and a comparison of two different proportions is done in this method.